Prevent body from rotating in Box2D

Question

I am currently using Box2d, more precisely the Java port jBox2d.

I have a circle that is colliding with other circles when falling (all those circles form a kind of a crank, see picture below).

Naturely, the circle begins to rotate when falling. But I would like to prevent it from rotating so that the friction is much higher.

I know that, thanks. But we are doing computer science, a physics engine is supposed to allow you to change the standard physics. And I would like my circle not to rotate. — Undo, Jan 26 '13 at 13:13

Pavel · Accepted Answer · 2013-01-26T13:51:58.193

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To prevent body from rotating set fixedRotation = true at BodyDef or call setFixedRotation of Body (if you need run-time change behavior).

edited Jan 26 '13 at 13:51

answered Jan 26 '13 at 13:38

Pavel

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Actually, I tried all fixedRotation = true and angularDamping and everything you would imagine on the BodyDef object but nothing worked. Though, I finally manage to get it working by using setAngularDamping(200) on the body object itself on runtime. I may try setFixedRotation on the body object as well. – Undo Jan 26 '13 at 14:34
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Looks like you doing smth wrong, fixed rotation MUST work. Check density of your fixture, it must be more then zero. I had such trouble because of this thing. – Pavel Jan 26 '13 at 17:08
Using .SetFixedRotation(true) on the Body (not the BodyDef) worked in box2dweb. – Deepak Joy Cheenath Jul 25 '13 at 16:30

score 4 · Answer 2 · answered Nov 21 '13 at 12:14

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In the runtime you want to set set rotationfixed then

b2Body body;  
body->SetFixedRotation(true);

answered Nov 21 '13 at 12:14

Singhak

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score 0 · Answer 3 · answered Sep 04 '16 at 16:51

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Fixed rotation means rotation at fixed axis in physics,so isFixedRotation=true; may not solve this problem,but setting angular damping to such a high value can prevent from rotating

answered Sep 04 '16 at 16:51

Kharak

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Prevent body from rotating in Box2D

3 Answers3