Problems with displacement maps not rendering

[hachejay]

Hello,

I'm having a problem getting displacement maps to render properly.

If I create a material using a bitmap texture and a bitmap displacement map, changing no other properties to the "generic" material, it display fine in the preview and if I add it to a simple object in a file with nothing else in it, it renders just fine. (image 1)

However, as soon as I start adding other geometry to the scene, the displacement will no longer render. (image 2)

The only way I have found to get it to render again is to apply the material to everything in the scene, which is hardly useful! (image3)

I am doing something wrong along the way? I can't figure it out for the life of me!

Thanks in advance.

H

[SonyBoy]

Could it be something to do with Vray's per-object displacement and subdiv attributes? It shouldn't make a difference but it's worth a look.

One artist where I work has been having some strange similar issues with bump maps, i.e. his scene will not render bump with a file texture. Works fine with a procedural, but a file texture that has previously been fine causes the render to fail.

[Mousa_SA]

Hi,

Just make each object you draw as a group or component, then every thing will be fine, also be sure to apply the displaced materials to the front face (white face) and the back face (blue face) or apply it directly to the group.

[konstantin_chaos]

Hi guys,

V-Ray internally handles displacement based on the objects / meshes in the scene.
In SketchUp these would be Groups and Component definitions.
And because of that managing the displacement used in a material is not a trivial task.

That's why the best approach in SketchUp is to apply the displacement material to the Group with all the objects that need to be displaced.
Keep in mind that there will be only one displacement texture and set of options per group.
If the faces in the group use a different material their displacement options will be ignored.
The Group material doesn't have to be visible in order for the displacement to work (all the faces or sub-groups in the group can use different materials).

And by the way:
We have plans to change the displacement assignment workflow in the future.
The cleanest way in which we can improve it is to have the displacement assigned to objects and remove it from the material options.
What do you guys think about that? Will it be too big of a change in the workflow?

Regards,
Konstantin

[hachejay]

Amazing, thanks a lot everyone!

Groups and components solved my problem fine. Though I noticed that on more complicated models it was more forgiving if I made sure to add things together and keep solid geometry!

Reversing faces is a good pointer too, on planar surfaces this was actually the case that sometimes the displacement was going the wrong way and I hadn't noticed due to the camera angle!

Not sure I'm seasoned enough with V-Ray yet to comment on workflow improvements, but many thanks for getting me on my way there!

H

[Mousa_SA]

Hi Konstantin,

This change could be a surprise for most of us, but it will be useful and has these benefits.

1-Displacement will work directly for who use it at first time, without any confusing of why it doesn?t work.
2- Displacement in general is a sensitive case and should be used for specific objects which are near the camera, that will save much memory so far objects will use Bump only without any need to duplicate the material.
3-That will add a possibility to add different materials for the displaced object, I suppose it would work like fur.

But that required some new features like copying Displacement options from object to other in the object Asset editor.
Also, that may required a way to filter V-ray objects (vrmeshs, vrscenes, furs, V-ray planes, displacement and clippers) in the Asset Editor.

Edit: Also it would be useful to avoid any hang from the material editor when it works with the VFB at the same time.

[konstantin_chaos]

Hi Konstantin,

This change could be a surprise for most of us, but it will be useful and has these benefits.

1-Displacement will work directly for who use it at first time, without any confusing of why it doesn?t work.
2- Displacement in general is a sensitive case and should be used for specific objects which are near the camera, that will save much memory so far objects will use Bump only without any need to duplicate the material.
3-That will add a possibility to add different materials for the displaced object, I suppose it would work like fur.

But that required some new features like copying Displacement options from object to other in the object Asset editor.
Also, that may required a way to filter V-ray objects (vrmeshs, vrscenes, furs, V-ray planes, displacement and clippers) in the Asset Editor.

Edit: Also it would be useful to avoid any hang from the material editor when it works with the VFB at the same time.

Hi Mousa Abu Doush,

You are right about the surprise. We'll have to be backwards compatible I think, which is not at all trivial.

As always, your feedback is highly appreciated.
I'll write these thing down and use the information when we start working on the new implementation.

Regards,
Konstantin

[Mousa_SA]

Thank you Konstantin!