CuMotion Robotics Examples issue

Omniverse Isaac Sim
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1

Isaac Sim Version:

6.0.0
5.1.0

Operating System

Ubuntu 26.04

GPU Information

  • Model: 3090
  • Driver Version: 590

Detailed Description

When running the path planning robotics example on isaac sim 5.1.0 compared to 6.0.0, the 5.1.0 version seems to run better and actually tends to avoid the walls, whereas when running the 6.0.0 version of the example, that has cumotion alot of the time it tends to collide with a wall. When colliding with the wall it seems to stop moving as well until the wall is removed. Why does this example work better with the Lula version and not the Cumotion version? Could this be due to some underlying update that hasn’t been implemented.

Steps to Reproduce

  1. Open Isaac Sim 5.1.0 and then go into robotics examples.

  2. Go to manipulation then run path planning after placing a wall infront of the block (while still making the cube reachable for the franka)

  3. Repeat the samething with isaac sim 6.0.0.

3

Hi @asadel.ali,

Thanks for the detailed report. This difference is expected and comes down to how the two examples build their collision world rather than a cuMotion regression — but there are a couple of things worth checking.

In 5.1, the Path Planning example uses the Lula RRT planner. It does two things that make it very conservative: it explicitly registers every wall you add with the planner, and it loads a robot description with inflated collision spheres (franka_conservative_spheres_robot_description.yaml). That combination gives the arm a wide berth, so it reliably routes around walls.

In 6.0, that example was replaced by the cuMotion Graph Planner example. cuMotion builds its collision world automatically from prims that have a physics collision API within a region around the robot — it does not track visual-only geometry. So the first thing to check:

  1. Does your wall have a collider? Select the wall, and in the Property panel confirm it has a Collider/collision API applied (Add → Physics → Colliders Preset). If it’s visual-only, cuMotion can’t see it and will plan straight through — which matches the “collides with the wall” behavior.
  2. Re-plan after placing/moving the wall. The Graph Planner plans once against a snapshot of the scene and then executes that trajectory open-loop; it doesn’t reactively re-plan mid-motion. After you add or move a wall, press Plan again so the new obstacle is included.

The “stops moving until the wall is removed” part is actually cuMotion working correctly: if the goal or the path is blocked, the planner returns no solution (you should see a “Planning failed: Unable to find a valid path” message), and the robot holds position. Removing the wall lets the next plan succeed.

If the wall does have a collider and you’re re-planning but the arm still grazes it, then it’s a margin-tuning issue — cuMotion’s default obstacle inflation in that example is small (1 cm), versus the deliberately inflated robot spheres the old Lula example shipped. Increasing the obstacle inflation or using a more conservative robot sphere config closes that gap.

4

Hi Michalin,

Thank you for your response. I have added a collider to the wall, though I added a rigid body with colliders preset as for some reason I could not just select colliders preset. I hope this does not cause a major change. After doing this though, I have noticed that the Franka tends to smash the wall away just to reach the block. I also noticed that I do not receive this “Planning failed: Unable to find a valid path” message, instead occasionally when it cannot find an approach angle it will say "No plan could be generated for target position ", this is probably due to distance or me not having the collision preset set at that time.