I did stand for my model, and I want to do support edges on 3mm at all faces. I did this everywhere by this method: I press ctrl + R, created loop cut, bring it to the end of the face and then move it, like G + X + 3mm. When I got the last loop cut, I faced a problem: I cant move loop cut on Z axis, because face is oblique. I looked for how I can solve this, maybe move loop cut not on the Z axis, but move on normal axis. I hope you understand, there are model and picture, where I did what I want, but I need exactly straight cut.
- Subdivide edge one time.
- With Edit Mesh Tools add-on set edge length (before this you need to apply scale by Ctrl+A> Apply> Apply all transforms or (in 3d Viewport) Object> Apply> Apply all transforms).
- Switch to any orthographic view (top, bottom, left or other) and extrude vertex by pressing Ctrl and enabled (in 3d Viewport in Edit Mode) Options> Auto Merge> Split Edges and faces (on top).
- Do this with all sides, removing duplicates if needed. You can check edge length by using Overlays> Measurement> Edge Length (in the 3D Viewport).
You can do the same thing with the Knife tool, but the Knife won't work in all situations.
Also, one of the ways: Bevel edges with settings: segments - 2, profile - 1. Bevel has differrent modes (Offset, Width and other), we need Offset. For bevel modifier you can do vertex groups where you need and bevel just them.