Z Depth and opacity

[re vit]

Hi!

How could I make Z Depth pass 'respect' my billboard's opacity (just like alpha and vraywirecolor passes)?

Any hints? Thank you in advance!

[WAcky]

I use the zdepth render element and it works fine for me.

 

What version are you using.

How are you generating your zdepth pass?

[re vit]

1.I use 1.5 sp2.

2. I simply add vray z-depth in render elements.

Edited December 8, 2009 by 1rv

[WAcky]

interesting. Are you using a standard vray material?

 

Can you upload a simple scene for me or someone else to have a look at?

[DanGrover]

One trick it to assign every material in a scene a falloff map to the diffuse slot. Make this map black to white via distance from camera on the z-axis. Set the distances in here to your near and far points and you should be good to go. This way, the opacity maps remain. I'm not sure how well it'd fair with displacement maps, though - I'm not sure if the falloff would be applied pre- or post-displacement - if the former, it won't work, if the latter then it should, but I haven't tested it.

 

I actually wrote a script a while ago that automatically sets this up for all materials in your scene, but as I'm mostly an MR user, it doesn't support VRayMtl and I don't have it with me atm!

 

But it should work if you do it manually, I think!

[Stephen Thomas]

I think this was a bug that has now been sorted in SP3.

[re vit]

Neither standard nor vray mat work. Here is simple scene.

I use 'tree shop' (scriptspot dot com/3ds-max/tree-shop)

for billboarding. In case you don't have it I converted one plane to mesh.

@Dan:

Could you apply this trick on my file and repost it please? I'm not sure

I understood it well.

@Stef.:

If so no more questions.

Edited December 8, 2009 by 1rv

[Ernest Burden III]

One trick it to assign every material in a scene a falloff map to the diffuse slot. Make this map black to white via distance from camera on the z-axis.

 

That is brilliant!

 

I had come up with a similar trick many years ago with Lightscape by using all white materials and black fog rendered to 16bit. Depthmaps should always be rendered to at least 16 bit! Otherwise, you will end up with visible banding not only in the map, but in the images you use it to modify.

 

What is good about both my old method and this newer one is that you can keep any and all clipping maps and any reflectivity you want to use. If your regular render has areas with strong reflections, you will appreciate the depthmap including that. You can even use multipass layers to separate reflections from the base diffuse (without reflections) channel.

 

Options are good.

[Stephen Thomas]

In the OP's case he'll need to remember to keep the opacity maps in place for the billboard objects which makes it a little more laborious than a simple global override material though.

 

You can still use an override for the majority of objects in your scene, just be sure to exclude your opacity mapped objects from it and create new materials for these with the same falloff map in the diffuse slot.

[erickdt]

Or he could do the free upgrade to VRay SP3 or SP4...

 

E

[Stephen Thomas]

Or he could do the free upgrade to VRay SP3 or SP4...

 

E

That would be the sensible option.

[Hoa Dinh]

VRay ZDepth doesnt work with opacity map in Vray sp2.

You can try like this guy, very helpful. He used fog effect:

http://forum.asgvis.com/index.php?topic=6263.0

[DanGrover]

On a similar subject, does anyone know how to get around the anti-aliasing issue with Z-Depth-based Depth of Field? That is, AA smoothes the edges but adding a tiny gradient from one colour to another colour. In a greyscale pass, this equates to the edge of a white object over a black background appearing grey. This looks much better than a jagged line, but of course when the pixel luminosity is used to define depth, that grey section then becomes a bit of space between the white and black bit, screwing up the depth blur. On the other hand, if you don't use AA (but did on the renders), your DoF doesn't look right because it's all jagged.

 

Any solutions? The best solution I've found is to render in layers - ie, foreground, middleground and background. But this increases rendering somewhat and seems a bit tedius in post - is there a better way?

 

(Or should this have been a thread unto itself?)

[Nic H]

as far as opacity and zdepth - upgrade to new SP, problem solved (if you have a legit version)

 

if you need smooth AA on your Zdepth use a falloff black / white map set to distance blend as a vray extratex element.

[amer abidi]

Z-Depth images do not fully support standard max opacity channels. Im not sure about Vray, I think it has been tackled in SP3, but MR cutout maps are fully supported.