Texture showing through another Material (Object)

[jakub007]

Hi everyone,

maybe someone here can help me. I am using camera mapping tool from micha which he shared here https://discourse.mcneel.com/t/wish-...apping/1231/12 and it works absolutely wonderful. But somehow the texture is "showing through" objects as you can see in this example. Any idea how i can get rid of this? The Photo is just a generic texture where i set the texture placement to environment and mapping type to screen. I already found out that this type of mapping only works with CPU and not GPU and that the prepass is showing more of this photograph on the gray material than the final image, but i am stuck and don't know what to do now to get rid of it completely.

original image

rhino viewport with generic gray material for the street and screen mapping for the photo on building meshes


when rendering

finished render cars showing through in the background


thanks
jakub

[Micha]

Hi Jakub,

the independent projection tool is changing the texture UV coordinates of meshes so that a texture looks like projected from a camera view point. The mesh and the UV should work in GPU and CPU mode. The UV are independent from the used render engine.

I don't understand why you additional enabled the V-ray screen mapping. Screen mapping makes that the mesh UV are ignored and the texture projection is done by V-Ray. This method has a issue (the projected texture looks bad in reflections) and maybe the V-Ray screen mapping doesn't fully work in GPU mode.

Is your street material reflective? If yes, than you see the V-Ray screen mapping issue. Reflection of screen mapped objects looks like transparent. So, if the reflection of the street show the houses (with screen mapping), than you get this issue.

It should help if you disable the screen mapping so that the the UV of the meshes are used. So you should get a solid camera projection.

Sidenote: the screen mapping issue is one of the frustrating issues for me since it cause trouble but it isn't accept as a bug. This issue "is normal and expected behavior with screen mapping".
https://forums.chaosgroup.com/forum/...material-issue

But maybe 2021 is the time to talk about a fix for the issue.

[jakub007]

Micha, thanks for your reply. I have tested some settings and here are my findings.

I am not sure anymore if the texturemapscreenspace works as it should in my case.

If i disable the vray screen mapping and just use the 2d UV Channel mapping, than i can render with CPU and GPU. However the Texture is not projected correctly with the texturemapscreenspace. It is not the screen projection as when i use the vray screen mapping. But the texture even with its impreciseness has a advantage of doing what i would expect. It is "baked" in position if i rotate the view afterwards, which could be useful if i would want to do a small animation movement in that street space.

This is how it looks when i only use the the texturemapscreenspace without vray screen mapping. I select the objects where i want to apply the camera projection, i am in the camera viewport and run the command at this is how it comes out. But at least the cars are not showing through


And the reflectiveness of the street material... I think i understand the behavior that you describe. The reflection doesn't reflect correctly, as shown by the examples in the other topic. And that should be fixed even if it seen as a feature and not a bug. But the gray street material is the absolut basic generic v-ray material. No changes. So that material shouldn't have any reflection whatsoever... That is why it seems to me that there is something else wrong with vray screen mapping. Or does the generic material have some reflection already?

I am very grateful for your input.

[Micha]

Screen mapping script: unfortunatly the quality of the mapping depends on the mesh density. Maybe you find a way to increase the density (weaverbird?, quadremesh?, ..). Best you setup your photo as viewport background and set the viewport ratio to the image ratio. Than you can adjust the view until mesh and background match. Than start the script.

I don't understand why the generic v-ray material shows a reflection if the reflection color is black. Additional you could add a raytrace attribute and disable reflection. Or is there an overseen infinite groundplane of Rhino?

[jakub007]

Micha this worked like a charm Perfect. I used quadremesh and it all looks and behaves as it should. Thank you. As for the reflection behavior, i still don't get it why i what acting like that, reflection color was black and rhino infinite was turned off. maybe i should report it as a bug.

I tested it only on the buildings in the front, but it works now.

If anyone is interested, i am using this so i can generate relatively quickly different moods for the same image without having to map and model everything. I just take a picture when it is overcast so i don't have strong shadows which predetermine the sun settings.