Modification Of Miter Angle Calculation

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Joined: Tue Apr 05, 2016 8:44 pm

Modification Of Miter Angle Calculation

Postby trapperii » Tue Apr 05, 2016 9:16 pm

Like so many others I'm a newbie searching for and unable to find a solution to this particular problem. I need the trig calculation modification to calculate a different configuration of a compound angle.

Here is my FreeCad configuration:
OS: Windows 8
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4671 (Git)
Branch: releases/FreeCAD-0-15
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

See the attached image. I'm trying to create the four sides that will fold at 45 degrees into the existing four extensions that are at 45 degrees. The miter angle calculation of Miter = tan-1[tan(angle1) * cos(angle2)] doesn't work for this configuration. Can someone supply the correct trig calculation? Trial and error results in something very close to 61.5 degrees.
I was successful in making the typical compound angle "picture frame" configuration and thought this modification would be a good learning opportunity to learn this FreeCad technique.
SideCalculation.PNG (11.27 KiB) Viewed 598 times