I’m working on an object imported with Stepper, the mesh had a hole (see attached screenshots).
When I highlight the edges and fill the face the hole is fixed as you would expect but the shading is weird.
Auto smooth is on for the normals but the angle option is greyed out for some reason, I guess due to the nature of an imported stp file.
Is there any way to fix this shading issue?
Most likely has custom normal data that you have to clear.
Can you point me to how I would find out if that’s the case?
If you enable wireframe view (on the view mode menu) you can see how the geometry looks.
One quick fix is to recalculate normals just in case there is way to fix something.
Generally when you import something, rarely you get quad based polygons, usually they are full of triangles. If the geometry is triangle based then you have no other choice than to dissolve triangles and try to make them quads.
Another quick fix is in Edit Mode to hit [Alt-J] so you turn triangles to quads automatically, but since this works in a random way you won’t get the correct result but at least it will reduce the clutter a bit.
Then instead of having to make 100% full retopology you could work only on the most visible and large surfaces, other surfaces that are not in full view or are too small when looked at an optical view distance you can leave them as is. Take into account rendered shadows or textures and you have much better way to find only the surfaces that need improvement.
Thanks for your input.
I’ve already tried to turn tris to quads, recalculate normals etc., none of which could solve the issue even a bit.
I’ve had a closer look at the opposite side of the object which doesn’t have the hole and it’s not just one face but several. Since this is a CAD file converted I’m assuming that this cannot be solved in Blender without messing up the shading.
Happy to be proven wrong though.
Under the object data tab (the triangle), there’s a section labelled geometry data, , if it has any, (and the greyed out angle value suggests it does), you’ll see the option saying “clear custom split normals”, (normally it would say “add custom split normals”). Simply click that, the auto-smooth angle value can now be edited, (I normally set it to 30 to 35), then, assuming your normals are calculated correctly and that face isn’t flipped, your shading should be ok.
You are a hero, this unlocked the angle option and really fixed the issue! Thank you so much!
No worries, it was something that initially baffled me. You tend to find it a lot on objects imported from other software as they use custom split normals as a means of what in Blender would be called marking sharp. You can still split edges in Blender, either manually in edit mode, or using the edge split modifier, but most times, you just use smooth shading and adjust the auto-smooth angle.
Yeah for sure, I’ve gotten project files which came out of CAD software and there is definitely a lot of funny stuff going on. Not the first time doing this and every time there is another issue to work out. Wish Blender was able to handle CAD files natively.
