Canvas depth or distance ? / control depth range possible ?

cgidesign

Two questions:

1. Can somebody tell me what the difference is between depth and distance canvas? They seem to be identical in my tests.

2. In other 3d sofware I can adjust the range of the z-depth pass - meaning at which distances the pixel should be white and black. Is that possible in DS Iray too?

 

Matt_Castle

1) Depth is the adjacent distance along the camera's axis, Distance is the hypoteneuse. At least, I think that's the right way around. It usually doesn't make much difference unless you're using a very wide lens. I think depth is strictly the more accurate for doing a focus blur, but distance might be useful in some cases.

2) It's an EXR file with 32-bit floating point output, anything that can manipulate that properly (newer versions of GIMP can) will allow you to pick your white/black points afterwards.

cgidesign

Thanks for the info, I am fine with using depth for now.

But out of curiosity: how to translate this information into understanding the DS scene?

Hypotenuse and adjacent are fine from a theoretical standpoint but what does it mean in the scene?

I am not even sure if my assumed position of the camera is correct.

Matt_Castle

For something in the centre of the image, it makes no difference; for things offset to the centre, it's a matter of whether you're measuring the shortest distance to the flat plane perpendicular to the camera (which is accurate as far as using it to fake focus, because focus is projected onto flat film/sensor elements), or the diagonal distance.

However, because camera angles are usually quite a narrow angle, the difference in these distances is usually small.