Smoke completely white in Z-Depth-channel

[OPKJoe]

Hey,

I'm having some problems with PhoenixFD and VRayZDepth-channel.

I have three objects with nozzles generating some smoke.
These objects have a certain distance to each other,
so in the VRayZDepth-channel the nearest object is in a light grey,
the middle object is a medium grey and the third one is very dark, almost black (all as it should be).
But the emitted smoke is very white with no difference in depth.
It seems as if the amount of white decreases a bit - parallel to the smoke density, but it's still very white.

Is the zDepth-channel not supported yet or what am I doing wrong?

Thanks in advance!

Kind regards,

Joe

[Ivaylo Katev]

the z-depth for the transparent object is meaningless and because of this the atmosphere objects have no z depth channel.

[OPKJoe]

Sorry, I don't quite know what you mean by that.

Attached you can find two pictures - normal render output and zDepth.
Shouldn't the smoke be in the same grey-tones as the cylindrical objects?

[Paul Oblomov]

Use geometry mode, I guess you can extract Z then.

[Ivaylo Katev]

hm, that is really weird, seems like the smoke affects the z channel.

[OPKJoe]

I switched the first simulator-box to Geometry Mode, but it looks even stranger:
This is not a region render!

You can't see through the simulator so the end cap of the second cylinder is hidden.
The Smoke looks completely different
The box gives some strange reflection on the nozzle.
And last but not least -> the zDepth for the smoke looks fine, but the rest of the simulation-box is white

[Ivaylo Katev]

in geometry mode you have to increase the max transp level of vray to a big enough value, abut the size of the box dividet by the cell size. i.e. to a value bigger than the steps that the volumetric shader makes.
i just tried it and it works, produces meaningful z depth value. of course it's slower than the atmosphere mode.

[OPKJoe]

Shure, I even read it in the manual but didn't keep it in mind.
Now it works perfectly. The render times are much higher, but I guess that's the price I have to pay for z-information

Thanks for your help!

[flat]

I want PhoenixFD_AtmosphereZdepth elements.
(atmosphere mode z-depth pass)

[Ivaylo Katev]

well, definitely we need some additional render elements...

[möbius]

Oh yes, 1+ vote for that.

I'm just in finishing one of our most recent projects and recognized the same problem. But in our case the rendertimes way to high with geometry mode because there are allready high without phoenix.
But beside an extra zdepth element for phoenix, wouldn't it be possible to consider it in the regular VrayZdepth element as well in some way?

[Paul Oblomov]

Hm. Why wouldn't you render z-pass in geometry mode with grey material applied on top ? Or black...

[möbius]

So, when you say Geometry Mode do you mean also Solid Mode?

[Paul Oblomov]

Maybe I am