Hi,
I’m having trouble getting the contype/conaffinity working properly in Isaac Gym.
I’ve created a minimal MJCF example which reproduces my issue:
<worldbody>
<body name="root" pos="0 0 0">
<body name="box1" pos="0 0 0">
<geom name="box1" type="box" size="0.1 0.1 0.1" contype="1" conaffinity="2"/>
</body>
<body name="box2" pos="0 0 0.4">
<joint type="slide" axis="0 0 1"/>
<geom name="box2" type="box" size="0.1 0.1 0.1" contype="4" conaffinity="8"/>
</body>
</body>
</worldbody>
From Mujoco’s collision documentaion, two geoms will collide if the expression (contype1 & conaffinity2) || (contype2 & conaffinity1) evaluates to true. From the above example, it should evaluate to false since none of the contype and conaffinity from both geoms share a common bit. When I run this in Mujoco, I’m getting the expected behaviour where box2 phases through box1.
However, when I import and run this in Isaac Gym, box2 collides right on top of box1. I’ve made sure to set the collision_filter to -1 when I called gym.create_actor().
Is this a bug or am I misunderstanding how contype/conaffinity work?