yade-users team mailing list archive

Thread
Date

Re: [Question #691115]: Question about the "0.05" in (O.bodies[i.id2].state.jointNormal1.cross(nRef)).norm()>0.05)

To: yade-users@xxxxxxxxxxxxxxxxxxx
From: Jérôme Duriez <question691115@xxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 04 Jun 2020 08:55:57 -0000
Reply-to: question691115@xxxxxxxxxxxxxxxxxxxxx
Sender: bounces@xxxxxxxxxxxxx

Question #691115 on Yade changed:
https://answers.launchpad.net/yade/+question/691115

    Status: Open => Answered

Jérôme Duriez proposed the following answer:
Hi,

This line wants to check whether two unit normal vectors are different (or not equal).
(please ask if more explanation are necessary here)

If they were equal (including the n1 = - n2 case), their cross product
would be strictly the zero vector, with a zero norm. Because we were
maybe not too ambitious in terms of precision here, we did not check
against zero but against 0.05.

You can see this as a 5% tolerance for error (responsible for false
positive in equal comparison). Or as the fact that two vectors whose
directions just deviate from 2.9 degrees are here considered as equal
(even though they're not)

-- 
You received this question notification because your team yade-users is
an answer contact for Yade.