Gazebo simulation uses complex collision geometry

[nickswalker]

I've noticed that I have to run quite small stepsizes to get reasonable behavior from the simulator (see #40) and end up getting about half realtime performance. One part of the simulation that jumps out for possible performance optimization is the collision geometry. Currently, the URDF reuses the display meshes for collision bounds:

stretch_ros/stretch_description/urdf/stretch_main.xacro

Lines 39 to 47 in 203726e

	<collision>
	<origin
	xyz="0 0 0"
	rpy="0 0 0" />
	<geometry>
	<mesh
	filename="package://stretch_description/meshes/base_link.STL" />
	</geometry>
	</collision>

These should use simplified meshes or primitives where possible.

[vatanaksoytezer]

So I agree that we should use simplified geometries (and will send a PR for that), the bottleneck here is realsense rather than the meshes. I am going to open a PR to make realsense closed by default, so far I have been %99 real time always with realsense closed vs %40 real time with realsense.

[nickswalker]

Fixed in our fork:
Visual

Collision