[0.17] pocketing problem

[m0n5t3r]

Hi all

I'm getting an annoying issue with a thing I'm (re)designing (because the original mysteriously broke when I changed the spindle radius): the last pocket results in an all-black model and broken mesh output:

Screenshot from 2017-04-15 21-30-30.png (11.03 KiB) Viewed 646 times

the original somehow works (almost identical, apart from the inner radius):

Screenshot from 2017-04-15 21-34-15.png (27.08 KiB) Viewed 646 times

edit: sorry, I was half asleep and forgot...
OS: Ubuntu 16.04.2 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10802 (Git)
Build type: None
Branch: master
Hash: 10ce910c03347a90712327a7cc7be2bcdee13afc
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0

[chrisb]

Please read the IMPORTANT: Please click here and read this first, before asking for help link above and post your FreeCAD info.

Edit: It is even more important as you seem to have used a developer version.

[NormandC]

Hello m0n5t3r,

Edit: It is even more important as you seem to have used a developer version.

To add to that, please edit your topic and add [0.17] to the subject title.

You have not properly constrained Sketch011 under Pocket009. You made a common mistake when constraining arcs: using a coincident constraint along with a tangent constraint on the objects. You should only use a tangent constraint between their end points, and nothing else. Using a coincident constraint and a tangent constraint as you did creates a precision issue.

This is how you should constrain an arc and a line to be tangent to each other:

phpBB [video]

If you delete the existing coincident and tangent constraints and replace them as shown in the video, you'll fix the issue.

[m0n5t3r]

You have not properly constrained Sketch011 under Pocket009. You made a common mistake when constraining arcs: using a coincident constraint along with a tangent constraint on the objects. You should only use a tangent constraint between their end points, and nothing else. Using a coincident constraint and a tangent constraint as you did creates a precision issue.

This is how you should constrain an arc and a line to be tangent to each other:

phpBB [video]

If you delete the existing coincident and tangent constraints and replace them as shown in the video, you'll fix the issue.

TIL; thanks a lot!