View Issue Details

IDProjectCategoryView StatusLast Update
0003180Part[FreeCAD] Bugpublic2018-01-14 15:07
ReporterwmayerAssigned Towmayer 
PrioritynormalSeverityminorReproducibilitysometimes
Status closedResolutionfixed 
Product Version 
Target VersionFixed in Version[FreeCAD] 0.17 
Summary0003180: Wrong normal of part object
DescriptionSometimes the normals of a part are completely wrong which leads to strange rendering artefacts.

The problem already exists since v0.15. Version 0.14 was not affected.

Attached is a BRep model, the Inventor layout created by v0.14 and that of v0.17.
TagsNo tags attached.

Activities

wmayer

2017-09-09 12:10

administrator  

shading_issue_014.iv (9,577 bytes)
shading_issue_017.iv (9,601 bytes)
shading_issue.brep (7,692 bytes)

wmayer

2018-01-14 15:07

administrator   ~0010763

The issue most of the time appears when the shape has some defects. But then computing the vertex normals from the (u,v) nodes of the triangulation gives bad results and affects the rendering. An alternative is to compute the normals from the triangles of the tessellation which e.g. in this case gives the expected result -- that's how it was implemented in the past. This simplifies the visual inspection of broken shapes.

To activate the old rendering set User parameter:BaseApp/Preferences/Mod/Part/NormalsFromUVNodes to false

https://github.com/FreeCAD/FreeCAD/commit/a701c71ed8961e7f4770da12acdf0314fa815464

Issue History

Date Modified Username Field Change
2017-09-09 12:10 wmayer New Issue
2017-09-09 12:10 wmayer File Added: shading_issue_014.iv
2017-09-09 12:10 wmayer File Added: shading_issue_017.iv
2017-09-09 12:10 wmayer File Added: shading_issue.brep
2018-01-14 15:07 wmayer Assigned To => wmayer
2018-01-14 15:07 wmayer Status new => closed
2018-01-14 15:07 wmayer Resolution open => fixed
2018-01-14 15:07 wmayer Fixed in Version => 0.17
2018-01-14 15:07 wmayer Note Added: 0010763