Thicken object not right in FBX Unreal

[Capprim]

Hi!
I did an object with splines, extrude and thicken. In C4D looks right but inside Unreal Engine has no thickness, just flat. See the originalExitBasementStairs01.c4d

[Dr. Sassi]

Hi Capprim,

Is one of these two files working for you?

CV4_2025_drs_24_MOno_01.c4d
CV4_2025_drs_24_MOno_02.c4d

"Double Sided Geometry" or "Two Sided" must be enabled (In Unreal) to "see" the polygons. The model you shared was not aligned with the Normals. In Unreal, if nothing has changed, the idea is to show only a polygon's "front" side to save render-time, etc.

The same effect can be seen in Cinema 4D when you use the Backface Culling shortcut N~P. The same (first N, then P) brings you back.

I fixed the Main Menu> Mesh> Normals> Align Normals function for you. Model …_02.c4d also has the N-Gons removed, and the mesh is a little bit optimized.

Please let me know if that works for you.

Cheers

[Capprim]

Hello!

Both models work! How did you fill the wall in the bottom with a polygon? If I use Close polygon, it makes a single polygon the whole bottom. I need just the thickness of the wall.

[Dr. Sassi]

Thanks for the reply, Capprim,

It's nice to "hear" that it works for your project.

The parts on the bottom: I used the Polygon Pen to close the long parts, and the CMD key was used to bridge the two edges each time, and with that, I had the four largest polygons in place. Which defines the remaining "holes" in a much better way.
Then I used the Close Polygon for the quarter-round "edges".

All the best

[Capprim]

Dear Dr.Sassi, Is there any tutorial with this part you describe? I can't replicate it. Besides, can't send you pictures. Thanks

[Dr. Sassi]

Hi Capprim,

Please have a look here; it is not a tutorial but a quick "pointer" (no audio)
https://projectfiles.maxon.net/Cineversity_Forum_Support/2024_Clips_DRS/20241209_Filling_Complex_Polygon.mp4

Let me know if that works for you. Download the file for better viewing quality.

Cheers

[Capprim]

Hi Dr.Sassi! Now I understand the process! Thanks so much!

[Dr. Sassi]

You're very welcome, Capprim.

I'm glad this little clip helped.

Enjoy your project!