Rendering Corona Volume Grid in Render Elements

Corona Corona for 3ds Max Feature Requests
1

I would like to start a quick discussion about how Corona Volume Grids are expected to be handled by different render elements. Please express your opinion how it should be working with each render element, and provide example workflows if possible (e.g. “I would like to render fire in front of a character and then be able to adjust the color of both the fire and the character behind it in post using masks”).

—> Here is a simple scene to experiment with, saved in Max 2018 format: [
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Original thread:
https://forum.corona-renderer.com/ VDB's not holding out in some AOV's

List of all Corona render elements:

Alpha
CESSENTIAL_Direct
CESSENTIAL_Emission
CESSENTIAL_Indirect
CESSENTIAL_Reflect
CESSENTIAL_Refract
CESSENTIAL_Translucency
CESSENTIAL_Volumetrics
CGeometry_NormalsDotProduct
CGeometry_NormalsGeometry
CGeometry_NormalsShading
CGeometry_UvwCoords
CGeometry_Velocity
CGeometry_WorldPosition
CGeometry_ZDepth
CInfo_NetworkRenderDebugging
CInfo_RenderStamp
CInfo_SamplingFocus
CMasking_ID
CMasking_Mask
CMasking_WireColor
CShading_Albedo
CShading_Beauty
CShading_BloomGlare
CShading_Caustics
CShading_Components
CShading_LightMix
CShading_LightSelect
CShading_RawComponent
CShading_Shadows
CShading_SourceColor
CTexmap

Current volume grid + render element behavior and my initial suggestions (I may be sometimes wrong though, so please share your thoughts):

Alpha - already included
CESSENTIAL_Direct - already included
CESSENTIAL_Emission - already included
CESSENTIAL_Indirect - already included
CESSENTIAL_Reflect - already included
CESSENTIAL_Refract - already included
CESSENTIAL_Translucency - already included
CESSENTIAL_Volumetrics - already included
CGeometry_NormalsDotProduct - invisible
CGeometry_NormalsGeometry - invisible
CGeometry_NormalsShading - invisible
CGeometry_UvwCoords - invisible
CGeometry_Velocity - invisible
CGeometry_WorldPosition - invisible
CGeometry_ZDepth - invisible suggestion: should be visible
CInfo_NetworkRenderDebugging - n/a
CInfo_RenderStamp - n/a
CInfo_SamplingFocus - works as expected
CMasking_ID - invisible suggestion: should be visible
CMasking_Mask - invisible suggestion: should be visible
CMasking_WireColor - invisible suggestion: should be visible
CShading_Albedo - invisible
CShading_Beauty - already included
CShading_BloomGlare - already included
CShading_Caustics - n/a
CShading_Components - already included
CShading_LightMix - already included (rest unassigned)
CShading_LightSelect - already included (rest unassigned)
CShading_RawComponent - already included
CShading_Shadows - already included
CShading_SourceColor - invisible suggestion: should be visible
CTexmap - invisible

vdb-re-res.zip (922 KB)](https://forum.corona-renderer.com/index.php?action=dlattach;topic=28378.0;attach=122292)

2

Internal link accessible only to the Corona team:
(Internal ID=477530807)

3

I may be responding to this thread in bits and pieces to try and keep information as bite-sized as possible.

By having the VDB invisible in some AOV’s, is the renderer wasting time sampling pixels behind the VDB, even though they are never visible in the beauty pass? That seems inefficient.

I guess what I am saying is that the VDB should be visible in all AOV’s for maximum render efficiency.

4

Also, can we please have VDB’s appear in more AOV’s, like normal and depth, much like how other renderers can like Arnold.

Arnold_5_1280x353.jpg
Arnold_5_1280x353.jpg1280×353 120 KB

5

So based on your feedback so far, other than what I wrote in the 1st post, you would like to see the VDBs in:

  • normal elements (shading, geometry, dot product - if possible)
  • velocity
  • Z-Depth
    Correct?
6

Yup. Another must have would also be the ability to add VDB objects to the ‘CShading_Mask’ render element.

I think it would be great to also have the following if possible:

  • base colour
  • raw lighting (similar to the geo version, where the VDB is shaded grey, hough I’m not sure what other tech settings would need to make this happen, as I have never seen this in another renderer before).
7

What exactly would be included in such “base colour” render element?

  • raw lighting (similar to the geo version, where the VDB is shaded grey, hough I’m not sure what other tech settings would need to make this happen, as I have never seen this in another renderer before).

According to my test, the Volume Grid is already included in the CShading_RawComponent element. Is this about something else?