Problem with displacement

[vicke50]

Strange things happen with disp.

First of all, I've made a rectangle 10mx10m, white face up.
I've imported a bitmap (the roof displacement map in this post) over the white face of rectangle.
Modify this roof material adding the same map to displacement (amount 20 for test)
Group rectangle surface and border lines
Render.... no disp effect

WHAT????? WHY????? I don't know. Until yesterday I did it like that. It worked for me in previous versions and I think with this release as well.

I made another rectangle same dimensions
Grouped surface and border lines
Applied roof material to the group (from outside the group)
Render..... WORKS!!!!!

I used this first method for years because it's the easiest way for adjusting textures on surfaces.

I tried again applying several materials on surface from inside the group keeping the roof disp bitmap, and disp geometry is still working works again, but I can't easily adjust the disp map position

It seems that disp bitmap affects only to the group for geometry, but not for materials from inside the group. I don't know if this is the way to do it from now or a bug.

Tested with W10, SU 2017 and 2018, VfS 3.06.01.

Regards.

Thanks, when I apply the material from the outside of the component it work fine except 20 is a bit big for displacement

[pabloarias]

Thanks, when I apply the material from the outside of the component it work fine except 20 is a bit big for displacement

Yes, I think that 4 or 5 is enough for your texture map. But I appreciate that someone from Chaos should tell us something about this displacement behaviour.

[konstantin_chaos]

Hi Pablo,

First of all, I've made a rectangle 10mx10m, white face up.
I've imported a bitmap (the roof displacement map in this post) over the white face of rectangle.
Modify this roof material adding the same map to displacement (amount 20 for test)
Group rectangle surface and border lines
Render.... no disp effect

The workflow that you've described should work without any issues.

On the other hand there are edge cases in which the displacement might not work when applied to faces.
The thing is that in V-Ray (Core) the displacement can only be assigned to geometries and not to materials while from a user standpoint in SU it's the opposite.

Because of that the following behavior can be observed:
> Every group or component definition in SketchUp becomes a single V-Ray geometric object after you hit the render button (and can only use one displacement)
> If there are multiple materials applied to faces in the same definition V-Ray uses a single Multi-material applied to the definition to distribute the materials
> If any of the face materials (sub materials) has displacement chances are that all the faces in the group might or might not be displaced. There is always one sub material controlling the displacement effect per definition (it's 'randomly' picked)
> If you want to ensure that a specific material controls the displacement of a group you can just apply it to the group. The materials assigned to faces will still take care of the texture placement

To make things more visual I've recorded the following video:

We will do our best to improve the displacement workflow with future updates.

I hope that the information here will help you manage displacement more easily.
Best regards,
Konstantin

[vicke50]

Thanks for all the help I have get, have now found a new displacement map that create a roof more like roof popular in Sweden (after invert).

[peerman]

I think this has always been the case. You must assign the displacement material to the group and not only to the faces within that group.

Best,