topic How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it? in Fusion Design, Validate & Document Forum

How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it?

harrison.friedes — Sat, 06 Dec 2025 09:17:29 GMT

I'm modifying an STL I found online. This piece fits into a larger piece, and I'd like to change the symbol on this piece. For simplicity's sake, I'd love to use this mesh rather than try to recreate it with the exact right clearances.

I can't find a way to do this within the Mesh window, and when I convert the mesh to a solid, I'm not sure how to make changes effectively given all the triangles.

Please see the shape with the "L" shaped hole and the "L" insert attached below for reference.

Re: How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it?

dsouzasujay — Sat, 06 Dec 2025 11:00:42 GMT

Hi @harrison.friedes ,

We can do but it depends upon various factors, number of mesh facets and with multiple tries.

Working directly from the mesh is a good approach when you want to preserve the original fit and clearances.

Here’s how I handled it:

1. Insert the mesh and create face groups

After bringing the STL into Fusion, I used Edit Feature(Direct Edit), Then used Create Face Groups. This helps isolate the “L”-shaped region so it can be removed cleanly instead of trying to edit triangle-by-triangle.

2. Delete the “L”-shaped hole region

With the face groups in place, I deleted the faces that form the “L” shape. This closes up the opening in the mesh and prepares it for conversion.

You may need to repeat this step several times to delete the fillet in the L shape

3. Convert Mesh → BRep

Once the mesh was cleaned up, Finish 'Direct Editing'

I used Mesh → Modify → Convert Mesh to turn it into a solid BRep body. After conversion, the model becomes far easier to edit and modify without dealing with all the small mesh triangles.

4. Now you can cut any new shape or letter

With the body now in BRep form, you can sketch whatever symbol or letter you want and use standard solid modeling tools (Extrude, Cut, Emboss, etc.) to create the new design.

I’ve attached an image and the .f3d file showing the result so you can see exactly what the workflow looks like.

Re: How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it?

lauri_barnhart — Thu, 11 Dec 2025 14:08:09 GMT

Hello, @harrison.friedes,

Did the information provided by @dsouzasujay help you and answer your question?

If yes, please click on the "Accept Solution" button. This will assist other community users in finding and benefiting from this information.

If not, please do not hesitate to give an update in this thread so all community members receive an update on the progression of your question, and can suggest next steps that may be helpful for you to achieve what you're looking for.

All the best,

Lauri | Community Manager

Re: How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it?

harrison.friedes — Sat, 13 Dec 2025 20:54:20 GMT

This is super helpful, thank you!

Re: How do I fill the "L" shaped hole on this mesh, and then cut out another shape from it?

harrison.friedes — Sat, 13 Dec 2025 20:59:09 GMT

This helps a lot, thank you!