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Found 5 results

  1. Indirect reflection noise

    So this might be a question of mantra settings in general but I am having problems getting rid of indirect reflection noise, it seems like no matter how high my settings this pass is coming out extremely noisy and it is showing up in the final render. I have read through all the docs regarding noise and read through the forums but since mantra changes with every release I don't know what information is still relevant. For instance I read the practical upper limit for pixel samples was 6x6 unless you have heavy DOF or motion blur. I have no idea what extreme settings would be for anything else though like sampling quality on lights or min/max pixel samples. The docs say in some cases you have to increase min ray samples for indirect reflection/refraction noise, but I read elsewhere not to increase that. What is the workflow there, when should this be increased? And how does that affect reflection/refraction quality, which seems to be a global multiplier? Also on the noise removal docs it says as an example 100 max indirect ray samples to achieve a clean image, is that referring to "enable indirect sample limits" rendering parameter on a shader? Is there not a more global way to set that or is that what sampling quality on each light is doing? However increasing that per light doesn't seem to make any difference. I should mention I come from a vray background so that is the workflow I am used to, if anyone can draw any parallels. Also this actual scene doesn't really matter, these are more general questions about newer mantra settings and when to tweak what Quick info about my scene- Still image, no DOF or motion blur, no environment light, just 3 area lights with sampling quality of 9 I do have some fine displacement which might be part of the issue, set shading quality to 3 on that object. Here are my render settings (refl and refr limit at 5, no diffuse bounces, color limit 5). Everything else is default Indirect reflection pass- Here is the comp zoomed in a bit, you can see there is visible noise on the black spheres and the displacement, there is also some square artifacting happening, my guess is the displacement is just too fine for mantra to dice properly resulting in a moire pattern type of effect but that wouldn't explain the square artifacting (that is in the raw exr, is not jpg artifacting) Any help on this would be greatly appreciated
  2. Is there a way to boost the indirect diffuse contribution of objects/lights/shaders in Mantr'as PBR render? I know arnold has this built into the light which is very handy. I was hoping for something similar in Mantra, but for the life of me I cannot find anything...
  3. Hi - when using the mantraSurface shader, or building a surface from physicalSSS or surfacemodel, I find that the SSS shading does not receive indirect illumination. Have a look at the attached image. Bounce light from the card is visible on the underside of the sphere when shaded with simple diffuse, but neither the single scatter or multi scatter pick up those contributions. Is there anything that can be done to include indirect paths in SSS calculations. Or is that an RFE? cheers
  4. Hi there, I am trying to integrate a simple box into a photograph that I found on the web. The idea was to just experiment with matching lighting and shadows. In my scene, I have created a grid for the ground, and roughly lined it up with the objects in the photopgraph. I then placed a box on top of the grid and used a distant light, and an environment light to light the scene. I applied a shadowmatte to the ground plane to catch any shadows occurring on it which has given me a nice alpha channel in which to composite shadows. My problem is that in the scene, the dog is casting shadows with a slight blue tint to it. I would like to match my box shadow color to the dog's shadow color. I understand that I can apply a color to the environment light to match the color temperature of the photograph, thus matching the shadow colors too, but obviously this won't work with the shadowmatte as it contains no color information. Obviously if I were casting shadows on a mantrasurface or similar diffuse surface I would get the proper colors of the shadows, however I would like to achieve this effect using the photographic backplate. Is there any way of achieving this with shadowmatte or AOVs, inside Houdini? Or does this need to be faked in compositing? What would be the best approach to this simple object integration? Any help would be really appreciated! W. shadow_test_04.hipnc
  5. Hi guys, i have a question concerning light components in H13. I have the following case: I want a light that only contributes to direct diffuse illumination. According to the documentation it should be possible with the category syntax to do just that, however i cannot seem to get it working. Here is the use case: The candle on the table has no illumination. The illumination comes from a sphere light. The sphere light has indirect contribution turned off because of noise issues. However the sphere light still contributes to direct reflection, where only the pyro sim should contribute. I cannot seem to dissable everything but direct diffuse on the sphere light....