Carbon Fibre over "edges"

limpstar · March 11, 2021, 06:34:32 AM

Hey hello guys

I am using KeyShot 10. I created a carbon fibre material following this tutorial: https://www.youtube.com/watch?v=pQS7jX44Y7. In general it worked out well, but I have problems on the "edges". The fibres change direction at them, although these are not real edges as you can probably see on images. I tried different things; playing with the angle, splitting the surface or adding "Rounded Edges" with different angles, Edit Normals... Nothing happens, the fibres always change direction on these "edges", although in reality they continue more or less in the same direction. I've played a bit with Unwrapping and I have the feeling that this is the way to go, but I don't know what options or angle to choose. I somewhat get something of a solution, but the pattern gets clumsy forms like on the last render.
I added the material, the .bip and the corresponding .prt if anyone wants to try it on his / her own.

TGS808 · March 11, 2021, 10:56:56 AM

UV unwrap is the way to go. These may help...

https://www.youtube.com/watch?v=Oh4ibAlp9Q4
https://www.youtube.com/watch?v=0dU7kxOHIPw

limpstar · March 11, 2021, 02:21:31 PM

thx, appreciate it. his videos are very useful.

TGS808 · March 12, 2021, 05:16:40 PM

Using the Quick Unwrap, Unwrap Shell on this may work (and be an easy solution) but you have a super high number of pollys on this part. If you can, reimport it with NURBS info intact and then re-tesselate it in KeyShot. It'll make the unwrap process easier.

limpstar · March 13, 2021, 03:52:27 AM

I tried Quick Unwrap, but it didn't work, but I will try again. Not sure yet how to keep NURBS data when exporting from Siemens NX, but I'll have a look at it, thanks alot for the input.

TGS808 · March 13, 2021, 06:54:12 AM

Quote from: limpstar on March 13, 2021, 03:52:27 AM
Not sure yet how to keep NURBS data when exporting from Siemens NX, but I'll have a look at it, thanks alot for the input.

It's done on import and it depends on what you are importing. This is when importing an STP. I would think you'd get the option on all formats that contain NURBS data. (I mostly import STP and IGES)

limpstar · March 14, 2021, 01:47:18 AM

ah yes, never seen that, but I guess it is automatically activated, it doesn't change anything. But Re-tessellate helps a bit, I am trying this one out now.

TGS808 · March 14, 2021, 11:19:19 AM

Here's where I got it. I started from scratch using your .prt file. (I didn't realize you had included that.) I don't know if it's 100% perfect but it's the best I could get it. The pattern now flows from the top over the sides without any unwanted seams.

When I imported your .prt into KS, it had some extra geometry connected to the front so I removed that (using Fusion 360) to match the part in your .bip example file. Exported an STP from F360, re-tesselated it in KS, UV unwrapped it and then realigned the normals.

limpstar · March 15, 2021, 07:58:22 AM

wow, this is great, thx for your efforts! oh sorry for that, in my KS file i deleted those faces manually. I am not sure if this changes a lot. What options did you use to UV unwrap? Quick unwrap?
Would you might upload your stp so that I can compare your NURBS data to mine to see if there are already huge differences there (or does it look like on the image I posted in my first post?)?

TGS808 · March 15, 2021, 10:24:20 AM

Taking that part off of the front made this all easier to do, that's the biggest change.

When I get home later I can upload that STP though to be honest, I don't think there there was a very big difference between yours and what came out of F360. The real change came in KS after the re-retessaltion (which got rid of the triangle pollys on the top that were causing issues). To see the difference, just remove the material from the surface in the material graph to reveal the pollys. Almost more importantly, realigning the normals (which I had to do on your .prt file and my STP) really was key here. Each half was facing in the opposite direction from the other, split down the middle. So, even when unwrapped nicely, there were still seams showing because of the opposite normals. (It took me a minute to realize what was causing it.) The unwrap was done manually, not with the "quick" option. (I can post my steps later when I'm home and have time to screen shot)

TGS808 · March 15, 2021, 06:52:29 PM

You can have the STP but it's really no different than your .prt.

Here's a link to video of the steps taken. (It's too big to upload here)
https://we.tl/t-eSOioOSTcR

limpstar · March 16, 2021, 03:18:35 AM

hey thanks so much for this "tutorial", I highly appreciate your help. I am going to try this also for the next body parts.

TGS808 · March 16, 2021, 05:22:37 AM

I find that any time I unwrap something, there's a lot of trial and error involved because each part is different. Dries posted some other good examples here:

https://forum.keyshot.com/index.php?topic=25515.0

limpstar · March 17, 2021, 03:06:27 PM

alright, I am trying my best

thx again for your help