Bevel harden normals modifier, tool, and Python op all have bugs #58113

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Howard Trickey · 2018-11-28T15:15:46+01:00

Howard Trickey commented

2018-11-28 15:15:46 +01:00

System Information
Linux

Blender Version
Broken: 2.8, edbf15

Short description of error
Two separate bugs, each of which should be solved by refactoring and fixing the harden normal code in bevel.

the Modifier has two problems:
(a) one face (the last?) does not get hardened normals
(b) the other other faces get normals that are totally aligned with the face normals, not the area-weighted normals that the spec specifies. And it pays no attention to Normal Strength. The behavior should be the same as the behavior with the Tool. (And, it is not clear that the tool is doing the proper area weighting either - need to check.)
if you run the bmesh.ops.bevel operator from Python, it does not do anything to harden normals, if that is what the arguments specify.

Exact steps for others to reproduce the error

With default startup file, enable Auto Smooth in the mesh properties. Then add a bevel modifier and change the Normal Mode to Face Area. If you use a shiny matcap, and/or enable vertex per-face normals in Overlay, you can see that the face with index 5 gets normals that are the original vertex normals, rather than the expected hardened normals that the other faces get. The other faces get normals that align exactly with the cube faces, not a face-area-weighted average.
With default startup file, enable Auto Smooth in the mesh properties. The run this in the python console:

import bmesh
bpy.ops.object.mode_set(mode="EDIT")
bm = bmesh.from_edit_mesh(C.object.data)
geom = bm.edges[:]
bmesh.ops.bevel(bm,

                  geom=geom,
                  offset=0.1,
                  offset_type='OFFSET',
                  segments=1, 
                  profile=0.5,
                  vertex_only=False,
                  clamp_overlap=False,
                  material=-1,
                  hnmode='FACE',
                  strength=1.0)

bmesh.update_edit_mesh(C.object.data)

and notice that the per-face vertex normals remain split and are not all aligned (mostly) with the big faces.

**System Information** Linux **Blender Version** Broken: 2.8, edbf15 **Short description of error** Two separate bugs, each of which should be solved by refactoring and fixing the harden normal code in bevel. 1) the Modifier has two problems: (a) one face (the last?) does not get hardened normals (b) the other other faces get normals that are totally aligned with the face normals, not the area-weighted normals that the spec specifies. And it pays no attention to Normal Strength. The behavior should be the same as the behavior with the Tool. (And, it is not clear that the tool is doing the proper area weighting either - need to check.) 2) if you run the bmesh.ops.bevel operator from Python, it does not do anything to harden normals, if that is what the arguments specify. **Exact steps for others to reproduce the error** 1) With default startup file, enable Auto Smooth in the mesh properties. Then add a bevel modifier and change the Normal Mode to Face Area. If you use a shiny matcap, and/or enable vertex per-face normals in Overlay, you can see that the face with index 5 gets normals that are the original vertex normals, rather than the expected hardened normals that the other faces get. The other faces get normals that align exactly with the cube faces, not a face-area-weighted average. 2) With default startup file, enable Auto Smooth in the mesh properties. The run this in the python console: import bmesh bpy.ops.object.mode_set(mode="EDIT") bm = bmesh.from_edit_mesh(C.object.data) geom = bm.edges[:] bmesh.ops.bevel(bm, ``` geom=geom, offset=0.1, offset_type='OFFSET', segments=1, profile=0.5, vertex_only=False, clamp_overlap=False, material=-1, hnmode='FACE', strength=1.0) ``` bmesh.update_edit_mesh(C.object.data) and notice that the per-face vertex normals remain split and are not all aligned (mostly) with the big faces.

Howard Trickey commented

2018-11-28 15:15:46 +01:00

Added subscriber: @howardt

Howard Trickey self-assigned this 2018-11-28 15:18:00 +01:00

Howard Trickey commented

2018-11-28 15:18:00 +01:00

The proper thing to do is to share the normal hardening code by putting it in BM_mesh_bevel(), rather than the current strange mix of having some of the work done in that function but most of it done (separately implemented) in the modifier and in the editmesh code that runs after the BMOp bevel runs.

Howard Trickey commented

2018-12-02 12:35:08 +01:00

The main bug (#1) is fixed now, but still have to fix the problem where the bevel operator run from Python cannot harden normals,

blender-admin commented

2019-01-03 19:39:52 +01:00

This issue was referenced by aef01c47e6

This issue was referenced by aef01c47e6334b214520f14c72b01de99387f122

Howard Trickey commented

2019-01-03 19:53:50 +01:00

Changed status from 'Open' to: 'Resolved'

Howard Trickey closed this issue

2019-01-03 19:53:50 +01:00

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Bevel harden normals modifier, tool, and Python op all have bugs #58113