Question about bump mapping on back-facing surfaces.

[vlado]

Hello everyone,

I have a question about bump mapping on back-facing surfaces when using a regular VRayMtl material. There are two options and I don't know which one to choose If you can fill in the following form, it will be very helpful!
https://forms.gle/GcbWDfyVjAhp6ov5A

Best regards,
Vlado

[fixeighted]

I reckon having both options available would be great
Or is that super-tricky to implement?

[spyzor]

Was thinking the same thing .

Argh, wanted to see the results.

[Vizioen]

Very nice. I would go with option 1.

[Grigio18]

Option 1 for sure, it seems to me the most correct and useful.

[Ihno]

I'm definitely against option1. I have to deal alot with cad stuff and it's very likely to have flipped faces. I'd want the bump to stay consistent nevertheless. Also, to me it seems more logical if the bump would add "volume" to one sided faces. Thinking about leaves here. To have it optional would be best though.

[piotrus3333]

option 1. no point in changing this I guess?

Ihno messy cad meshes - you can use VRay2sidedMtl, back mat with inverse value in normal/bump.

[khoross]

I'm definitely against option1. I have to deal alot with cad stuff and it's very likely to have flipped faces..

have the same problem option 2 for me is the best solution. or have a switch botton for option 1 & 2.

[Mokiki]

Being able to choose would be nice if that isn't too much of a hassle to implement.

[kosso_olli]

I have to deal alot with cad stuff and it's very likely to have flipped faces.

Well, flip'em then. Flipped faces cause all kinds of trouble, not just with bump. Light cache calculations, refractions with fog, ambient occlusion, normal passes etc...
Having wrong sided faces in the scene is not a good practice.

[Ihno]

Let's not turn this thread into a general workflow and practice discussion.
I know very well (unfortunately) what kind of errors those things produce.
You've got my opinion on this question. That's all I wanted to throw in.
In the end it'll be option 1 anyway I'm afraid.

[vlado]

An option will probably be best in the long run; for the moment I’ve left version #1 and version #2 can be done with a 2-sided material, if needed.

Best regards,
Vlado