Z AOV rendering white. Other AOVs not rendering at all.

[Anonymous]

C4DtoA 2.5.2.1
Arnold core 5.3.1.1

New blank c4d scene with a light and some primitives spread around. I have a driver_png object. Its active AOV list consists of P, N, and Z (and beauty was removed). The driver_png object's parameters are all set to default except the File Path which is set to custom and the path is /render/$AOV.png

Having a display driver with the same AOVs and then using the IPR shows P, N, and Z are all correct. Nothing wrong so far. Clicking "Render to Picture Viewer" brings up the Picture Viewer, renders the current frame, but now the problem: ONLY the Z AOV is rendered to the path. The P.png and N.png files are non-existent. Z.png is a completely white image with no depth data at all (I double checked the pixels in nuke).

Simply switching the driver object from driver_png to driver_tiff mode and re-rendering produces the previously missing P and N files as .tiff files and they are now correct. Z.tiff is also still completely white with no depth data. driver_exr has equivalent results as driver_tiff.

What is going on? I just want these AOVs to be rendered as seperate .png files.

[peter.horvath6V6K3 · Accepted solution]

You can see in the log (console), that the png driver does not support VECTOR type AOVs, like P and N, that's why the files are not written. (Actually it should not support the FLOAT type Z AOV either.) You need a driver which supports 32-bit float data type, e.g. tiff or exr.

The Z AOV contains the absolute distance from the camera, it may display white because the distance in each pixel is likely higher than 1.

[Anonymous]

Thanks, Peter.

Can you elaborate on the Z depth AOV displaying pure white due to distance for each pixel being higher than 1? I don't entirly understand how Arnold would make that the case when it shows up just fine in the IPR.

I'll be rendering these AOVs to .tiff from now on.

[peter.horvath6V6K3]

Z is a float type AOV, so every value above 1.0 displays white. I see what's causing the confusion. The distance of the background is infinite (well, a huge number, just check the pixels), which is interpreted as black in the Cinema 4D bitmap of the IPR window. Not sure why, must be something how the bitmap casts to 8-bit values, yet the distance coming from the renderer is correct.