Dear fellow Blender enthusiasts, noob here.
I’ve been learning Blender for a few weeks now and usually I’m able to find solutions to the problems I encounter by searching the interwebs but this one has me stumped.
I’m modeling a chrome plated cover with a keyhole in the middle.
The cover is an extruded and beveled plane onto which I (knife)projected the keyhole shape which I then extruded to give it depth.
When I render the object though, I get visible creases in the chrome surface, even though all edges are in the same plane.
I have smooth shading turned on for the object and I’m aware thet setting Auto-Smooth for the mesh would solve the problem but it also makes all other edges of the mesh sharp again.
Can anyone suggest the correct way of going about this ?
Should I remodel the object with more detail for the rounded edges ?
This is a tricky little problem that you will have to continue to find solutions to forever.
The problem is to do with smooth-shading. There are two solutions to shading an object in Blender: flat and smooth. Flat shades face according to it’s direction (or normal), and smooth shades each vertex according to it’s direction (or normal)
The easiest solution to this is to swap to flat shading.
This appears to be from a boolean operation, or knifing the shape as you have done. Holes must have a place to terminate and be a part of the object. Yes the autosmooth will work as long as you adjust the tolerance (angle) to a good degree. And old trick would be to inset the offending face a bit to relieve “tension”, and yet another would be to triangulate the face, you can also triangulate through a modifier and set it to do it only at render. You can add more divisions to the geometry so that the verts of the hole are all accounted for over the mesh, or simpler still, create an edge from a different part of the hole to that corner. Subdivision can also solve this. I’m more than likely not covering all of the solutions to this problem, as there are many and are use case sensitive, but this should give you a few ideas.
As was said before, you find this happening a lot in cases like this, your solution will depend on where and how this happens.
Adjust the vertex normals to all point to the direction of the flat surface, instead of having them averaged between the flat front surface and surfaces around the curved edges. This uses custom normals which override auto smooth angle.
Alternative is to add control loops that creates extra faces near the curved edges, which does the same for vertex normals on the majority of the front surface. It limits the shading from averaged normals near the edges.