@dbase, I agree with @sebavan that converting to PBR material from our standard material will give you more power for your materials and a simple way to author a metal frame rail. The problem is that you will need to provide a couple more textures to make it work. The other thing that is a bit off in your frame mesh is your UVs. Unfortunately, if you have a texture like the one on your mesh, you need to be very careful with the UVs to make sure everything aligns correctly.
Since it’s faster for me to illustrate in DCC tools, I’m going to do that so you can see what I mean. The first thing I noticed is that the ribbon you are using is angled in UV space rather than aligning parallel to the texture. You can see this because of the angled highlight which is actually the highlight that runs along the left edge of your image.
Since you only have this one section of image and nothing else for the edge or back, we need to get a little creative with our UV layout. The front and back of the rail needs to mirror each other to keep the highlight on the outside of the rail. The side is a little more tricky. That’s because you will see a seam if you apply the texture to the side where the dark pixels on the right of the image fall next to the bright pixels of the left of the image. This sketch shows what it may look like with some visible seams where the contrast is highest:
So instead, you will want to pull a UV trick like this:
I quickly threw this rail together in Maya to illustrate, but you can see that I added a loop in the middle of the rail thickness. The coordinates in the image show you where each UV lies in UV space. So for the front and back you can see they are pretty standard with the miter moved in from the top and bottom of UV space about 0.07 unit.
The center loop is where it gets a little tricky. You align the front and back UVs of the face to the U0 axis and the center loop to the U1 axis. What this does is flip the texture in the center with the left edge of the face using the left pixels in the image, the center part of the face using pixels at the right edge of the image, then reversing the texture to end with the right edge of the face using the left pixels of the face. This creates a bit of a mirror in the middle which can be obvious if the texture has angles in it, but with primarily parallel detail, this should be minimal.
The final UV layout looks like this:
What this does is to bring the highlights into the edges of the rail and fakes a bit of a bevel on the edge.
Now, there is one more thing to be concerned with to use the PBR material and that is the need to supply a metallic, roughness, and normal texture to go with your base color texture. Ideally all textures are authored together for best results, but if you only have a base color texture, you can somewhat simulate the others, but it’s not going to be exact. You will need something like Materialize to generate the other textures. These solutions tend to work better to generate large deltas in height rather than subtle detail, so you will want to experiment with the settings.
Once you have the other textures, you can assemble your material to apply to your mesh. I would probably go the route of starting with a box and altering the positions of the vertices that represent the miter and then duplicating the mesh to make the frame. This way you can assign one material to a rail and clone it for the others.
The only other thing you will want for your PBR material would be an environment which can be made from any HDR image and we just made a video about how to convert HDR files for your scenes.
So you can see what I created, I saved out a glb of the rail I used to illustrate this with the computed textures. You can drag and drop the linked file into the sandbox to inspect the material and see how it is created. I know this is a lot, so please shoot back any questions you have about the process.
frameRailPBR.zip (6.1 KB)
