نور سنجی در عکاسی کتاب الکترونیکی آموزش کامل و کاربردی چاپ سیلک اسکرین آموزش کاربردی عکاسی دیجیتال آموزش راینو

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آموزش طراحي خودرو اسکچ و راندو (دستی + کامپیوتری) - کلاس‌های حضوری

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موضوع: آموزش تری‌دی‌مکس مقدماتی و آموزش کاربردی VRay

  1. "" #33
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
    بچه شمال کافه دیزاین
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    108

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    آموزش نکات کاربردی وی ری

    آموزش تنظیمات رندر وی ری

    آموزش Irradiance map

    Irradiance map modes: Rendering a static scene from multiple views


    Search Keywords: IR, Irradiance map, GI
    In this tutorial we will examine ways to efficiently render a static scene from multiple views.
    This is the scene we will use for the tutorial:
    We want to efficiently render several views of this scene, using the irradiance map.
    The different irradiance map modes will help us in this task.
    First open the starting scene.
    By default the irradiance map mode is set to Single frame. This allows us to render the scene from any view, but every time the irradiance map will be computed from scratch. There are two cameras in the scene. Render each of them:


    We could render a single view, save the irradiance map, and tell VRay to use that map, instead of computing a new one the next time. Since the irradiance map from the last rendering is still in memory (we have the Don't delete option in the On render end group set), all we have to do is open the Advanced irradiance map parameters rollout and click the Save to file button. Choose a file name, for example "test", and save the irradiance map.
    Now that we have map saved to disk, we have to tell VRay to use that map. Change the irradiance map mode to From file, click the Browse button and select the file we just saved. Re-render the image. Notice that now VRay does not calculate an irradiance map, but skips directly ahead to the rendering.
    Since no irradiance map is computed, the rendering is very fast. What if we want to render the first view at this moment? This is what happens:
    Clearly this is not what we want, but why does it happen? The irradiance map is only partially view-independent - meaning that a single sample in the irradiance map is valid for any view, but the samples for a given view are optimally generated for that view only. VRay will not calculate the irradiance map for parts of the scene that are out of view. If you check the Show samples option in the Indirect illumination rollout and render the scene, you can see where the actual samples are:
    Is it possible to render this new view using the old samples and add new ones only where it is necessary? The answer is "yes". Just set the irradiance map mode to Incremental add to current map. Remember that the current irradiance map is still in memory. Render the view:
    VRay has added more samples to the irradiance map. Here is a comparison of the old map (green samples) and the new map (red samples):
    Now, let us see what the scene looks like with the this map. Save the irradiance map to the same file, set the mode to From file, turn off Show samples and render:
    In fact it is not necessary to go through the whole save/load procedure every time. Set the mode again to Incremental add to current map. Change the current view to perspective view and render some more random views - simply change the view and render. Do this several times. Here are the views I rendered: (click an image for a larger rendering):


    After you render some views, save the irradiance map to a file by clicking the Save
    to file button. Save it to the same file as before. We are going to need this map in a moment.
    As a comparison, here is the last of these images, re-rendered with the irradiance map mode set to Single frame (which means that a completely new irradiance map was generated):
    Notice the increased render time - generating a new map is more costly than using the one already in memory as a basis.
    Let's go back to the saved irradiance map. Now it contains information for quite a large portion of our scene. We can use that to render other views without adding any more irradiance samples. Set the mode to From file. Choose a view that is roughly similar to a view you have rendered before and render:
    Note that we did not do any irradiance calculations for this image! We used only the irradiance map that we have computed so far. This is possible because the irradiance map already contained enough information to render this view, even though we have not rendered it before.
    If the irradiance map did not contain enough information, we would get artifacts as before, and would have to use the Incremental add to current map mode to fill in the missing information.
    As a conclusion, here is a basic workflow that can be used to render a static scene from multiple views:
    • First prepare the scene (geometry, materials, lighting etc)
    • Adjust the irradiance map settings for the required level of detail (e.g. chose a suitable preset) and tune the other render parameters.
    • Clear any previous irradiance map from memory in order to avoid weird results
    • Set the irradiance map mode to Incremental add to current map
    • Render as many views as you need. The first one will be slow, since a full irradiance map will be computed. Each of the next views will be faster depending on how relevant the memory irradiance map is to that view.
    • You can save the accumulated irradiance map to a file. That map can be used to render quickly other views of the scene, if required later on. To load the saved map, you need to set the mode to From file, enter the correct file name and render any image. You can then set the mode back to Incremental add to current map and continue rendering other views. If you are sure the map already contains enough information, you can simply leave the mode to From file.
    Note that if you make any changes in the scene (e.g. add/delete objects, change materials or lights etc) the irradiance map that is in memory will no longer be relevant to the scene and you will need to reset the irradiance map and start all over again.
    و خودت میدونی تمومه...الکی جو نده...

  2. "" #34
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
    بچه شمال کافه دیزاین
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    108

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    Rendering a walk-through animation


    Search Keywords: animation, walk-through
    General

    In this tutorial we will render a walk-through animation of a static scene, where nothing but the camera moves. We will use global illumination to light the scene, which makes the task somewhat complicated. GI is usually too slow to calculate from scratch and with sufficient quality for each frame of the animation. To optimize this process and save rendering time, we can use the fact that the scene is static and the camera is the only thing that moves. Most of the GI solutions used in VRay (irradiance map, photon map, light cache) are either fully or partially view-independent, and we can use this fact to reduce rendering times.
    For this tutorial, we will use the irradiance map as a primary GI engine, and the light cache as a secondary engine. To make the process easier to understand, we will render the scene in three steps.
    In the first step, we will calculate the light cache for the entire animation. In the second step, we will calculate the irradiance map. In the third step, we will render the final animation.
    Note that you don't have to use this method to render walk-throughs. You can always use a slower brute-force approach and avoid having to deal with all the issues around precalculating the various GI solutions. However, you pay for this with render times.
    Part I: Calculating the light cache

    1.1. Open the starting scene.
    1.2. Assign VRay as the current renderer.
    1.3. Set the Background color in the 3dsmax Environment and Effects window to RGB 252,252,252.
    1.4. In the Render scene dialog, turn Global illumination on and set both the Primary GI engine and the Secondary GI engine to Light cache.
    1.5. Set the Image sampler type to Fixed for faster previews.
    1.6. Turn on Show calc. phase in the Light cache rollout.
    1.7. Check the skylight Override MAX's checkbox in the Environment rollout.
    1.8. Set the skylight color to RGB 252,253,255 and HSV(156,3,255).
    1.9. Set the skylight color Multiplier to 4.0.
    1.10. Uncheck the Default lights checkbox in the Global switches rollout. This will remove the default max lighting in the scene and it will by lit only by the environment skylight.
    1.11. Go to the Camera rollout and change the Camera type to Fish eye.
    1.12. Uncheck the Auto-fit checkbox, change the Dist value to 1.0 and Curve to 0.35. We set the camera to Fish-eye to produce a more interesting effect.
    1.13. Render frames 0 and 360 for reference.

    The light cache doesn't look bad, but we will need to calculate it for the entire walk-through animation, and not for a single frame only. Note that this is not strictly necessary - we can render the animation with the light cache being calculated each frame; however, rendering it only once will save rendering time, especially for long animations.
    1.14. Set the light cache Mode to Fly-through. Make sure that the timeline animation range matches the range which you want to render. This is important because the light cache will look at the current timeline animation range when calculating the fly-through cache.
    Since all the light cache samples will be distributed among all the animation frames, we will need to increase the light cache Subdivs value. The exact value depends on the quality you want to achieve and on your specific animation. If the camera moves slowly, or the path is relatively short (e.g. just one room of a house) then you can use lower Subdivs value, since most of the samples will fall in the same place anyways. If the camera moves quickly or covers larger parts of the scene, you will need more samples to get adequate coverage everywhere.
    1.15. Set the light cache Subdivs to 2000.
    1.16. Render frame 360 for example. Note that although we render only one frame, the Fly-through mode forces the light cache to be computed for the entire animation:
    During the fly-through mode, the preview display of the light cache is not very useful, since it shows samples from the entire camera path. The following image shows the preview display while the light cache is being calculated:
    Now that we have computed the light cache, we need to see if it is good enough for our needs. We can do this by rendering several different frames with the same light cache.
    1.17. Save the light cache to disk, for example to lightcache.vrlmap.
    1.18. Set the light cache Mode to From file and select the saved file name.
    1.19. Change the Filter in the Light cache rollout from Nearest to None. Now we can see better the samples' size.
    1.20. Render frame 435:
    You can notice that in places where the camera gets close to a wall in the scene, the light cache samples are smaller and more noisy. This is because the light cache Scale is set to Screen by default. This is fine for still images, but for animation we would like a more even sample distribution. To achieve this, we will need to use the World option.
    1.21. Set the light cache Scale to World.
    Now we have to determine a good Sample size for the scene. This can be done, for example, by creating a geosphere directly in the camera viewport or a Tape object and using it to visualize the sample size. For our scene, a sample size of about 2.0 seems to be good enough (the scene is in Generic units). In general, you should make the Sample size as large as possible without getting artifacts (light leaks etc). Even if you are getting some light leaks, it may be possible to remove them by reducing the filter Interp. samples value.
    1.22. Set the light cache Sample size to 2.0.
    Keep in mind that when you use the World scale, you must make sure that your scene is not too large (e.g. with a large ground plane) or that the light cache samples are not too small, otherwise you can run out of memory for the light cache. This is not such a problem for the Screen mode, since surfaces that are far away from the camera will get fewer samples anyways. For exterior scenes, it is recommended to use the Screen mode always.
    1.23. Change the light cache Mode back to Single frame and lower the Subdivs to 500 just to check if the sample size is adequate. Here is an example of frame 435:
    The samples are equal in size everywhere and they are just big enough so we don't get artifacts on the image.
    1.24. Set the light cache Mode to Fly-through again.
    1.25. To smooth out the light cache a little bit, increase the the Subdivs to 3300.
    1.26. Change the Filter back to Nearest.
    1.27. Render frame 360:
    The calculation time is longer now due to the increased samples number.
    1.28. Save the light cache and set the mode to From file again.
    You may notice that the light cache file has become bigger in size. This is because there are more samples in the light cache, partly because of the World scale mode - the same amount of samples are taken everywhere in the scene (in Screen mode, the sample size increases as the samples get farther from the camera, which leads to less samples).
    Now we can render several different frames to make sure that the light cache is adequate for our animation.
    1.29. Render a few frames.
    It looks like the light cache is good and we can move on to the next part - calculating the irradiance map.
    Part II: Calculating the irradiance map

    Compared to the light cache, the irradiance map may take significantly more time to calculate. This is because the light cache provides a very crude and undetailed lighting solution. The irradiance map, on the other hand, takes care of the small GI shadows in the scene.
    Note that the irradiance map cannot be calculated through backburner. It must be calculated on a single machine. This is because we will use the Multiframe incremental Mode for the irradiance map.
    2.1. Set the primary engine to Irradiance map.
    2.2. Set the irradiance map Mode to Multiframe incremental.
    2.3. Check the Show calc. phase checkbox.
    Since the camera moves quite slowly, there is no need to render every single frame of the animation at this stage. We can get an adequate irradiance map by rendering every 10-th frame, for example. If the camera moves faster, we will need to render more frames, for example every 5th frame.
    2.4. Set 3dsmax to render every 5-th frame from the Common tab of the Render scene dialog.
    2.5. Turn on the Don't render final image option in the Global switches rollout, since we are not rendering the final animation yet and we don't need the final frames.
    2.6. Render the entire sequence.
    2.7. Save the irradiance map to file, for example, irmap.vrmap.
    2.8. Set the irradiance map Mode to From File with the saved file.
    Now we have one irradiance map for entire animation sequence. We can render a few frames to make sure everything is ok.
    2.9. Turn off the Don't render final image option.
    2.10. Render frames 0 and 360 from the animation:

    The two images above were rendered with the settings used for the final animation in Part III.
    Now we are ready to render the final animation.
    Part III: Rendering the final animation

    For the final animation you can use backburner with the saved irradiance map either on the client pc or locally on each server machine. In either case, you must make sure that each render slave can find the irradiance map in the location specified in the From file parameter for the irradiance map.
    3.1. Set the Image sampler type to Adaptive subdivision with Min/Max rate to 0/3 for better antialiasing quality. You can also check the Normals checkbox to avoid flickering problems with small details in the scene. 3.2. Make sure the irradiance map Interpolation type is set to Density-based. This will enable the irradiance map to pick the closest available samples from the cached solution.
    3.3. Set 3dsmax to render every single frame.
    3.4. Render the final animation.
    Here is the ending scene.
    Here is the final animation that you should get if you have followed the tutorial correctly (8 MB).
    Notes

    • We are not using glossy reflections in this scene, but if you are using them and not using the Use light cache for glossy rays option at the same time, then you can set the Secondary GI engine to None for the final animation. This is because you won't need the light cache and turning it off will save memory.
    Discussion

    In this section, we have added some questions about this tutorial that were asked on our online forum, along with the respective answers.
    Q: Did you render out to consecutive images and then compile the avi or was it straight out to avi?
    A: The animation was first rendered out to .png images, and then compiled into an .avi. That way, you won't lose all rendered frames if something goes wrong in the middle of the rendering... and also you can play with the compression settings later.
    Q: Why did you choose Multiframe incremental over Incremental add to current map mode? What is the difference between the two that would cause you to choose one over the other? I ask because Ive never used Multiframe incremental and have always used the Incremental add to current map.
    A: The only difference is that the Multiframe incremental mode will delete the map in memory at the start of the rendering. With the Incremental add mode, the current map is not deleted.
    Q: I just wanted to clarify... It is possible to use Incremental add to current map mode in conjunction with backburner without any problems (ie flicker)? Does backburner handle frame allocation ok without max saving any files? Reading your post above, I get the feeling you are suggesting that you need to send different sections of the animation to each render-node.
    A: Yes, you can render different sections on different nodes, but you must merge the resulting irradiance maps manually with the irradiance map viewer in the end, before rendering the final animation. Also, you must make sure that each section is allocated to one single render node only.
    Q: I must make an animation with a spray which you can see in the image upload, and I have many glossy reflect and refract, if I follow your tut how can I make my final setup? With lightcache for second bounce and Use light cache for glossy rays or without light cache and none for the second bounce? Does Use light cache for glossy rays and irmap in first bounce work fine?
    A: You can have the light cache saved with the irradiance map. If done so, you can actually just turn off secondary bounces which will save memory as you wont have to load the light cache. However, if you have the light cache help precompute the glossies with the Use light cache for glossy rays option, then you'll need to go ahead and load the light cache when rendering.
    و خودت میدونی تمومه...الکی جو نده...

  3. "" #35
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
    بچه شمال کافه دیزاین
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    VRay Photon Mapping Tutorial



    Search Keywords: photon, photon mapping
    In this tutorial we'll examine photon mapping in VRay and efficient ways to use it.
    What is photon mapping?

    Photon mapping is a technique for computing global illumination. However, in difference from the irradiance map, which starts tracing rays from the camera, photon mapping traces rays from the lights in the scene. The two approaches are not mutually exclusive, and indeed for best results the photon map and the irradiance map should be used together.
    The photon map has many parameters that allow for a lot of interesting results; here we will not discuss all possibilities but will just point out settings that are reliable and work well in most cases.
    Initial settings

    For all of our experiments, we will start with the following settings for the photon map (note that these may be different from the defaults):
    Convert to irradiance map - off
    Auto search distance - off
    Max photons - zero
    Convex hull area estimate - off
    Store direct light - on
    Retrace threshold - zero
    The only parameters that we will actually use are:
    Max density - this defines the resolution (spatial detail) of the photon map. Lighting information from the photon map is accumulated at a number of points on the surfaces of scene objects. This parameter defines the distance (in world units) between those points. Smaller values mean that the points will be closer to each other and there will be more of them. Larger values mean that the light samples will be farther away from each other and there will be fewer of them. Obviously, this parameter depends on the scale of your scene. Changing this parameter requires recomputing of the photon map, since it is used only while the photon map is computed.
    Search distance - this defines how lighting will be reconstructed from the surface points described above. You may think of it as blurring of the photon map. It should be larger than Max density, but the exact value depends on how blurry you want your photon map solution to be. Values of 2-5 times the value of Max density work well. Changing this parameter does not require recomputation of the photon map since it is used only during rendering.
    Additional parameters that we will keep at the default values, but which you may change as needed are:
    Bounces - this controls the number of light bounces; you can set it to whatever value you want; more bounces mean slower computation of the photon map. We will keep this at 10, but you you may adjust it as you want.
    Multiplier - this is a multiplier for the photon map; we will keep it at 1.0, but you may adjust it if you need.
    We have thus limited the parameters of the photon map that we'll use to just two - Max density, and Search distance. These are enough for controlling the photon map. Besides those settings, the quality of the photon map depends on the number of photons emitted from scene lights. More emitted photons mean a smoother and more accurate photon map. The number of light photons is controllable for each light from the Light settings dialog, accessible from VRay's System rollout.
    A simple example - the Cornel box

    We'll demonstrate the effect of those two parameter on a simple Cornell box-like scene.
    You can download the starting scene here (for 3dsmax 5). It includes a very simple setup of a closed space with differently colored walls and a spot light. The walls have VRay materials applied to them since currently photon mapping works only with VRay materials.
    Note that the spot light has inverse square falloff and quite a high multiplier. This is because real-world lights have inverse square falloff, and photon mapping produces inverse square falloff by default.
    This is what you get if you render the file straight away.

    Now turn on GI and set the photon map method for both primary and secondary bounces. Turn off Auto search dist, set Max photons to 0, Retrace threshold to 0.0, and Max density to 10.0:
    If you render, you should get this result:
    A bit dark, but this can be corrected by increasing Secondary bounces multiplier (in the Indirect illumination rollout) to 1.0. If you render again, you should get this:
    This renders quite fast, and it is quite a good approximation to the lighting in the scene. Obviously, it is far from being a good-quality image, but we will get there eventually.
    Now go to the Render dialog, and in the VRay System rollout, click the Light settings button. In the dialog that opens, select the spot light and set its Diffuse subdivs parameter to 500. This controls the number of diffuse photons emitted by the light (not directly though, the actual number of photons is the square of this number, in this case - 250,000). Close the Light settings dialog and render again:
    The photon tracing phase takes longer, but you can notice that the noise of the individual light samples is reduced, although the image is still splotchy. We can reduce the splotchiness by increasing the Search distance parameter. Set this to 40 and render again:
    The result is a lot smoother, although very blurry. Also notice the dark corners. Dark corners are not easy to avoid with this setup of the photon map, but the effect can be reduced to a great extent. Now set Max density to 5.0 and Search distance to 10.0:
    The effect of dark corners is reduced a lot, but the image is again noisy and splotchy. To decrease the noise, increase the Diffuse subdivs for the light to 1500:
    The noise of the individual samples is reduced again. Now we could increase the Search distance again to smooth the result, however we will do something else - we'll use the irradiance map to do the smoothing instead. In the Indirect illumination rollout, set the First diffuse bounce method to Irradiance map and choose the High irradiance map preset. If you render, you will get this:
    The Cornell box scene is a very easy scene for a global illumination algorithm, since there is very little occlusion (objects casting shadows and stopping the light). Next we will look at a more difficult example: the Sponza Atrium Scene.
    A more difficult example: the Sponza Atrium

    Now we will show how to use photon mapping on a more complex scene, the Sponza Atrium, which is modelled by Marko Dabrovic (http://www.rna.hr). You can download the initial scene here. If you render right away, the scene will look like this:
    Note that photon mapping does not work with skylight. This is because photons need a real surface to be emitted from. Therefore, photon mapping is not suitable for outdoor scenes. However, in scenes where skylight comes in from small openings like windows, you can "invite" the light in by putting VRay lights at those openings. In the case of the Sponza scene, we have put a VRay light at the top of the building, which is the only place skylight comes from.
    Now turn on Global illumination and choose the Photon map as both the first and secondary diffuse bounces method. Set the secondary bounces Multiplier to 1.0. Next go to the Global photon map rollout and turn off Auto search distance, set Retrace threshold to 0.0 and set Max photons to 0:
    Next, we must determine a good value for Max density. From that we will choose a value for Search distance.
    A good Max density value depends on the scene scale and the desired photon map detail. There is a Tape helper in the scene, measuring the distance between two columns. Its length is almost 6 units. So, a good value could be, let's say, one tenth of that distance. Set the Max density parameter to 0.6 and Search distance to twice that value, 1.2 and render. You should get a similar result:
    The result is quite blurry, so we'll obviously need lower values for Max density and Search distance. After some experimenting, we have found that 0.05 for Max density and 0.1 for Search distance produce the following result:
    Very noisy obviously, but the detail (the size of the spots) seems to be good enough. We get dark areas and bright spots because we don't have enough photons emitted from the lights. To fix that, go to the System rollout and click on the Light settings button. Select both lights in the scene and set the Diffuse subdivs to 500 (which means 500 x 500 = 250,000 photons from each light). Close the Light settings dialog and render. The photon tracing now takes longer, but the result is better:
    Still, we will need more photons for a good photon map, so set the Diffuse subdivs for the sun (the target direct light) to 2000 (which means 4,000,000 photons) and the the Diffuse subdivs for the VRay light to 2500 (which means 6,250,000 photons). Close the Light settings dialog and render. The photon tracing phase now takes quite a bit of time (several minutes), but the result is a lot better:
    In order to save time for subsequent renderings, you can save the photon map to disk: go to the Global photon map rollout and click the Save to file button. Choose any name for the photon map and save it. Then set the photon map Mode to From file and using the Browse button select the map you just saved. We can now play a little with the Search distance parameter to blur the photon map a little more. Set the Search distance to 0.4 and render:
    The photon map is smoother, but the effect of dark edges can be clearly seen. So, instead of using the photon map alone for GI, we will use the irradiance map to smooth the GI. Return the Search distance value to 0.1 and set the first diffuse bounce method to Irradiance map. Turn on the Show calc. phase option, choose the High irradiance map preset and render:
    Note that the photon map is view-independent. We can render a different view without recalculating the photon map (the irradiance map still needs to be computed, though):
    In this last image you can see some artifacts (splotches) in the corners where two surfaces meet. This happens because the photon map is too noisy in those areas, which is reflected in the irradiance map too. This is what the photon map looks like from this view:
    The noise is because light is more difficult to get into occluded areas of a scene. One way to reduce the noise in the photon map is to shoot yet more photons. Here is the photon map with 6000 subdivs (36,000,000 photons) for the sun and 5000 subdivs (25,000,000 photons) for the area light:
    Here is the same image, but with irradiance map as the first diffuse bounces method:
    Of course, shooting more photons means (much) longer photon tracing phase. Another way to reduce the artifacts is to increase the Search distance value, which will blur the photon map a little more; however this will also make the dark edges effect more pronounced. This image was rendered with Search distance of 0.2; the original low-resolution photon map was used:
    Yet another way to deal with the artifacts is by increasing the Retrace threshold value to its default value of 2.0. This will cause VRay to compute GI directly for secondary bounces near corners, instead of using the photon map. This means that the irradiance map will be slower to compute, but the corners will be somewhat better. The following image was rendered with Search distance 0.1 and Retrace threshold 2.0:
    و خودت میدونی تمومه...الکی جو نده...

  4. "" #36
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
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    VRay Displacement Mapping Tutorial


    Search Keywords: displacement, displacement mapping, 2D, 3D
    In this tutorial we'll examine displacement mapping in VRay. We will concentrate on the 3d displacement mapping method.
    What is displacement mapping?

    Displacement mapping is a technique for adding geometric detail to surfaces at render time. In contrast with bump mapping, which works by just changing the surface normal to create the illusion of surface detail, displacement mapping modifies the surface itself. Here is an example of the same object rendered with bump mapping and with displacement mapping:


    In the case of displacement mapping, the surface is actually modified, which leads to correct outline, shadow and GI. In the case of bump mapping, although the surface appears modified, the outline and the shadow stay the same.
    Note that displacement is different from other kinds of shading, since it needs to modify the actual object surface. Therefore an object must be displaced before it can be rendered. This is why in VRay displacement is represented with a modifier (although the modifier can take the displacement map from the object material).
    A simple example - a displaced sphere

    Start with an empty scene. Create a GeoSphere with a radius about 40 units in the viewport and choose VRay as the renderer. Apply some Standard material to the sphere.
    Applying the VRayDisplacementMod

    Go to the Modify panel and apply a VRayDisplacementMod to the sphere. If you render straight away, you will notice a slight displacement effect, like so:
    This is because VRay applies a simple noise displacement map when no other texture is chosen.
    Selecting a displacement map

    To select another map, click the texture button in VRayDisplacementMod. This will bring up the Material/map browser dialog. Choose a Cellular texture. To edit the newly created map, open the Material Edtior and drag the map from the button in VRayDisplacementMod to a slot in the Material Editor. Choose the Instance method when you drop the map.
    If you render again, you should get a similar result:
    Setting the displacement amount and shift

    To make the displacement effect more pronounced, increase the Amount value of VRayDisplacementMod. If you set it to 5.0 and render you will get something like this:
    The Amount value determines the maximum displacement amount (which occurs at places where the displacement map is white).
    You can shift the whole displacement map up and down by adjusting the Shift parameter. The effect will be to expand (for positive Shift values) or shrink (for negative Shift values) the displaced surface. Here are some examples of different Shift values:
    Note that the Shift parameter is an absolute value in world units. If you change the Amount, you will probably need to adjust the Shift too.
    Clipping geometry using the Water level

    The Use water level and Water level parameters allow you to clip parts of the object. Return the Shift value to 0.0, if you have changed it. Then turn on the Use water level option and set the Water level to 2.5:
    The geometry is clipped away for those places in the displacement map where the displacement value is below the Water level. Here are a few examples of different Water levels (assuming the Amount parameter is still 5.0 and the Shift parameter is 0.0):

    Water level = 5.0 (all geometry is clipped)
    The Water level parameter is also absolute in world units. If you change the Amount and/or Shift, you will probably need to adjust the Water level to get the same effect.
    For 3d displacement, the geometry is clipped on a sub-triangle basis - a subtriangle is either clipped away entirely, or completely visible (this is not the case for 2d displacement where clipping is more precise). Therefore, you may get a jagged effect at the clipped edges. You can reduce this effect by producing more subtriangles (see the next section).
    Displacement quality

    VRay does 3d displacement by subdividing each triangle of the original object into a number of subtriangles. More subtriangles mean better displacement, but will also take more memory and will increase the render time. To get a better idea of how many subtriangles you have, apply a Standard material to the sphere (if you haven't done so already) and turn its Faceted option on. This is important, as otherwise VRay will not only smooth the surface normals, but will also automatically apply a normals map that represents the normal of the perfect displaced surface, which will make the surface look a lot more detailed that it actually is. Also, switch off the Use water level option of VRayDisplacementMod, if it is on. If you render, you should get a similar result (click the image for a larger view):
    Here is a blow-up of this rendering to better show the individual subtriangles (click the image for a larger view):
    In addition, here is a rendering that shows the boundaries of the original triangles of the sphere. To do that, put a VRayEdgesTex map in the Diffuse slot of the material and instance this map into the Self-illumination slot. Set the Color of the edges in the VRayEdgesTex to red and the Thickness to World units:
    The quality of the displacement is determined by the size and number of the subtriangles. The main parameter to tweak is the Edge length. It determines the maximum length of a subtriangle's edge. This can be in world units or in pixels, depending on the View-dependent option. Lower values for Edge length mean smaller triangles and better quality. Here is the previous image rendered with various values for Edge length (with View-dependent turned on). Note that the View-dependent option refers to pixels in the original image, not the zoomed-in image you get with a blow-up rendering. This is why we were able to do a blow-up rendering to see the individual subtriangles better. Click the images for a larger view:

    و خودت میدونی تمومه...الکی جو نده...

  5. "" #37
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
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    خب بچه ها
    میخوام یه مبحثی رو بهتون یاد بدم که فکر کنم 100% کسایی که وی ری معماری کار میکنن واسشون حیاتیه!
    مبحث daylight اگه بخوام علمی ترشو بگم
    احساس میکنم آموزش های زبون اصلی زیاد به مذاقتون خوش نیومده واسه همین دارم ترجمه میکنم براتون
    پس به زودی ترجمه فایل آموزشی نورپردازی daylight رو واستون آماده میکنم
    واقعا مشغله کاریم اجازه نمیده اما به خاطر همتون که تا اینجا همراهیم کردین تا تهشو میریم
    فعلا
    و خودت میدونی تمومه...الکی جو نده...

  6. "" #38
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
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    خب بهتون قول دادم و بالاخره واستون یه فایل آموزشی رو ترجمه کردم
    این آموزش بهتون نورپردازی daylight رو به وسلیه vraysun و نورهای مکس یاد میده...نورپردازی مطابق واقعیت که حتی ساعت و دقیقه و ثانیه و حتی تاریخ روز و ماه و سال رو بهش میدین تا جهت جغرافیایی خورشید مشخص شه...
    ----------------------------------------------
    تو این آموزش ما اول یک vraysun که توی daylight مکس وجود داره تو صفحمون جانمایی میکنیم (ساعت و تاریخ فراموش نشه)
    ----------------------------------------------
    1) در بالای صفحه روی منوی creat کلیک کنین سپس systems سپس daylight system
    حالا کلیک کنین و درگ کنین daylight رو تو مرکز صفحه (مطابق شکل)
    ----------------------------------------------
    2) حالا باید یه سری پارامترا تغییر کنه...
    مثل شکل همین تغییرات رو بدین
    ----------------------------------------------
    3) حالا باید ساعت , دقیقه , ثانیه و روز , ماه , سال رو به سیستم بدیم...
    اندازه این پارامترا به مرور زمان دستتون میاد که کدوم اعداد واسه کدوم موقعیت رندر بهتره...
    *نکته* مثلا دادن عدد 90 درجه به خورشید به ما حالت خورشید نیمروز رو میده
    *نکته2* قبل از اقدام به رندر باید vraysun رو تنظیم کنیم...همچنین میتونیم برای مانور دادن رو کادرهای رندر , دوربین بکاریم...
    ----------------------------------------------
    4) حالا میریم به vraysun parameters و تنظیمات رو انجام میدیم ( مطابق شکل)
    ----------------------------------------------
    5) حالا vrayphysicalcamera رو تو صفحه جاگذاری میکنیم و روی شئ مورد نظر تنظیم میکنیم دوربین رو
    ----------------------------------------------
    6) حالا میریم به modify panel و distortion رو تنظیم میکنیم روی 25/. این حالت لنز دوربین خیلی به لنز دوربین توی دنیای واقعی نزدیکه
    سپس vignetting رو به 3/1 تغییر میدیم...این تغییر کمک میکنه به فرم تاریکی و سایه های کنج های کار ما
    آخرین تغییری که باید توی این منو بدیم film speed هست
    ارزش نوری (روشنایی) دوربین ما رو مثل دوربین های دنیای واقعی میکنه...تنظیم روی عدد 120 حساسیت به نور دوربین رو شکل میده ( تغییرات مطابق شکل )
    ---------------------------------------------
    7) رندر کار رو ببینید...هنوز جای کار داره...
    ---------------------------------------------
    8) خب بیاید سریع یه حرکتی بزنیم تا رندر واقعی تر شه...
    برید به customize setting و سپس preferences و گزینه Gamma & LUT سپس تنظیمات رو مطابق شکل انجامش بدین
    ---------------------------------------------
    9) حالا میریم به صفحه تنظیمات رندر و آیتم color mapping رو باز میکنیم...
    سپس تنظیمات مظابق شکل رو انجام میدیم
    *نکته* این تغییرات پارامتر ها باعث ایجاد یک فضایی که رنگهاش جذابیت بیشتر دارن میشه...
    ---------------------------------------------
    10) حالا آیتم Indirect Illumination رو باز میکنیم و تغییرات مطابق شکل انجام میدیم...
    *نکته* طبق اکثر کارایی که خودم هم انجام میدم موتور اول irradiancemap و موتور دوم light cache انتخاب میشه...این دو موتور جذابیت رنگی و نوری طبیعی رو به ما میدن
    ---------------------------------------------
    11) این صفحه تنظیم هم که کسایی که وی ری کار میکنن فکر کنم بدونین چیه...کیفیت رندر و تیک کنار light cache که سایه ها و نیم سایه ها و نقاط نور رو در حین رندر گرفتن بهتون نشون میده...
    *نکته* اگه سرعت سیستمتون پایینه کیفیت رو روی very low تنظیم کنین
    ---------------------------------------------
    12) تو آیتم light cache بستگی به سیستم کامپیوترتون داره...اگه سرعتش پایینه subdivs رو روی تقریبا 800 بذارین و اگه سرعتش نسبتا خوبه sabdivs که روی 1500 باشه کیفیت خوبی میده
    ---------------------------------------------
    13) خب کار ما تموم شد و اینم رند نهایی ما :
    ---------------------------------------------
    ***نکته مهم :
    تمام مفاد این آموزش به صورت تجربی بعد از یه مدت کار کردن دستتون میاد...سعی کنین برای فضولی هم شده با پارامترها و منو های مختلف بازی کنین تا حالت های مختلف دستتون بیاد...چون وی ری همش تجربه کاریه...
    و خودت میدونی تمومه...الکی جو نده...

  7. "" #39
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
    بچه شمال کافه دیزاین
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    لطفا سوالاتونو تو بخش اورژانس بپرسین دوستان
    ممنون
    ------------------------------------
    به زودی آموزش جدیدی از نورپردازی های وی ری میذارم براتون...
    اکه میبینین انقدر رو نور تاکید دارم چون اگه میبینین کارهای ماها با کارای اونور آبیا از نظر جلوه طبیعی بودن کمتر هست فقط به خاطر کمبود اطلاعات فنی نورپردازی هاییه که ما داریم اونم به خاطر اینه که تو ایران هیچ آموزش جامعی نیست و اونایی که ما پیششون یاد گرفتیم هم بلد نبودن که به ما یاد بدن!
    پس منتطر آموزش جدید باشین...
    و خودت میدونی تمومه...الکی جو نده...

  8. "" #40
    کارشناس 3DMAX‏ mamal آواتار ها
    تاریخ عضویت
    Apr 2009
    محل سکونت
    بچه شمال کافه دیزاین
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    سلام به همه و مرسی از لطفی که بهم دارین...
    مقدمه :
    تو این قسمت نورپردازی پنجره و نور خورشید که از محیط خارجی به فضای داخلی میتابه رو بهتون آموزش میدم...
    که بر خلاف تصوری که قبل یاد گرفتنش دارین اصلا کار سختی نیست و مثل بقیه حرکت هایی که تو وی ری پیاده میکنیم بعد از چند بار کار کردن دستتون میاد...
    همیشه گفتم بازم میگم...وی ری و مکس همش تجربس...مثلا توی مکس به این نگاه نکنین که وای چقدر منو و آپشن داره و من توش گم میشم...اول کاری که میخواین با مکس انجام بدین رو مشخص کنین و بعد تو همون فاز برین...وی ری هم که همش بازی با یه سری اعداد و حالات نوری ( شکست نور...سایه...نیم سایه...رفلکس و نویز و ... ) هست

    --------------------------------------------------------
    1) برای شروع یه اتاق ساده رو میسازیم و یه سری وسایل رو توش جاگذاری میکنیم...


    2) حالا روی پنجره هامون نور وی ری رو میذاریم طوری که جهت فلش نوری به سمت داخل باشه...


    3) حالا با نور direct target مکس , نور خورشید هم میسازیم و مرکز نور رو داخل اتاق میذاریم...برای جلوه دار شدن کار ترجیحا نور رو با زاویه به اتاق بتابونین...


    4) و در نهایت هم تنظیمات رندر وی ری :


    5 ) این چیزی که میگم تو بعضی از کارایی که حجم کارتون نسبتا بالاست به کارتون میاد اونم اینه که تو پروژه های سنگین ( از نظر مقدار داده هاتون به نرم افزار ) اول این کارا رو انجام بدین بعد رندرهای تستی رو بگیرین و زمانی که نور مورد قبولتون بود متریال بدین تا وقتی رندر تستی میگیرین زمان کمتری ببره...

    6 ) اینم رندر نهایی :


    *** در آخر بگم تمام این تنظیم های رندری که اینجا و هرجای دیگه وجود داره همش بر اساس تجربه بعد از تعداد بسیار کارهایی که انجام شده به دست اومده...یعنی بعد از چند وقت خودتون متوجه میشین به فرض برای رندر داخلی اعداد و آیتم ها چی باشه و برای محیط خارجی چی باشه...***

    ****سعی کنین همش با این اعداد بازی کنین و تفاوتها رو ببینین توی رندر چه شکلی میشه...آیتم هارو عوض کنین ببینین چی میشه...
    من خودم اون اوایل چند بار مکس و وی ری رو پاک کردن دوباره نصب کردم بس که ور رفتم باهاشون و همه تنظیمات به هم ریخته بود و بلد نبودم به اول برگردونم !****
    و خودت میدونی تمومه...الکی جو نده...

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