Displacement issue on polygon selection of specular material

[Jaydekay]

Greetings + thanks for stopping by!

I would like to put am embossed logo on a glass material by using a displacement image (think mason jar). I've put together a simple example file with a screenshot to help to illustrate.

I've run into two issues:

A. Logo tiling: When using ImageTexture's "Border Mode", the logo still tiles. I've tried both "white color" and "black color". See callout #2 in attached screenshot
B. Displacement is affecting the material in a strange way: As a workaround for issue "A", I've created a polygon selection, and applied the material with the displacement to this area only. The goal was to prevent tiling of the logo. However when I do this, the material looks different (lighter) than the neighboring material. Note that these two materials are exactly the same. The only difference is that the displacement material has a basic scale Transform node, an ImageTexture note, and a Displacement node (all other settings like IOR are the same). See callout #1 in attached screenshot

That said, I have a couple of questions:

- Is "A" a current limitation?
- Is "B" a bug, or is there a better way to go about this?

Thanks folks!

PS - I'm attaching both the scene file, and screenshot of my example setup.

[atome451]

Hi jaydekay,

A. Yes, as far as i know, it's a limitation. You shoud UV map your logo or reduce your polygon selection in height with some kniffe cuts.
B. I think the problem here is more a Transmission problem. There is no bug here. You should verify both values in your materials. I've tested here and it works fine.

I hope this will be usefull.

[Jaydekay]

Hey atome451, thanks for your reply!

A. Yes, as far as i know, it's a limitation. You shoud UV map your logo or reduce your polygon selection in height with some kniffe cuts.

Thanks for the suggestions. I actually used more knife cuts in the actual scene file, I just wanted to illustrate the tiling issue in the attached example file.

B. I think the problem here is more a Transmission problem. There is no bug here. You should verify both values in your materials. I've tested here and it works fine.

I have tried it several ways and still see the same issue. The materials are exact copies of each other. The only difference is one has a displacement on it. If I turn the displacement off the problem goes away and the materials are seamless.

I have also tried it with only the index channels turned on for both materials (all other channels off, except of course I use displacement on the logo material).

My only thought is that it may have to do with the fact that the mesh is double walled (the glass has an inside and outside), but then again in my mind this should not create these results, as I am only asking the material to deform in the embossed area, and everything else is exactly the same.

I have also tried black and white images, white and black images inverted, alpha images, 8 bit, 16 bit, 32 bit and the issue still remains.

Could you possibly post your working example scene?

Thanks again for your thoughts!
- J

[atome451]

Hi Jaydekay,

Here a sample file. I've modified the photoshop file to have a smoother displacement but in fact it wasn't necessary to remove your problem. As expected, it was a transmission problem.

I've played a little bit with your file for the fun. Sorry if it disturb you.

Glass Displacement atome451.zip

My result

(1.29 MiB) Downloaded 193 times

[Jaydekay]

Hi atom451,

That fixed it, you were right afterall. It was a transmission issue on my end for part B.

Thanks a lot for looking into that and sharing the file! I appreciate you taking the time.

Cheers + happy new year!

- J

PS - @aoktar: If you see this, great job on the plugin!

[aoktar]

Hi atom451,

That fixed it, you were right afterall. It was a transmission issue on my end for part B.

Thanks a lot for looking into that and sharing the file! I appreciate you taking the time.

Cheers + happy new year!

- J

PS - @aoktar: If you see this, great job on the plugin!

Thanks!