Help with SCMDeformableTerrain settings

[yueminzhang]

Hello,

I am recently running a demo using the SCM terrain, and find that when the terrain is initialized, the area outside the grids seemed to be solid. When I drove a viper outside the settled area, the viper wouldn't drop down. Is there any solutions to remove the mesh outside the visualized area?

Regards.

[Radu Serban]

The SCM terrain itself extends to infinity in the x-y plane, beyond the patch that you used to initialize it. The height of the SCM terrain beyond these limits is equal to the height of the closes (x-y) point that was initialized.

In other words, what you call “the area outside the grids” is not rigid, but rather deformable SCM terrain.  It is simply not visualized (one could also automatically extend the visualization mesh as the vehicle moves beyond those limits, but that was not of interest to me when I implemented this code).

 

What I fail to understand is why this is an issue to you. Why would you want the rover to “fall off the terrain”?  Supposedly, you are interested in keeping the rover within the bounds you defined – that should be done through other means (control of the rover).

 

--Radu

--
You received this message because you are subscribed to the Google Groups "ProjectChrono" group.
To unsubscribe from this group and stop receiving emails from it, send an email to projectchron...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/73792a4b-1089-4792-9f7c-e83a8f982951n%40googlegroups.com.

[yueminzhang]

Thank you for your explanation. 

Actually, I want to stitch two different types of SCM terrain together（with different parameters). When the terrain is uneven, it may happen that one terrain is higher and another is lower. This causes vehicles running on the lower terrain to be unable to make contact with the ground because of the extended SCM terrain from the higher one. Therefore, I want to find a way to fix the issue. Is there any solutions?

[Radu Serban]

I see. That makes sense.

In fact, I intend to eventually combine the RigidTerrain and SCMTerrain classes (or maybe provide a convenience wrapper class) to allow creating a complex scene with a combination of rigid and SCM deformable patches.  Unfortunately, that is not completely straightforward and I do not have the bandwidth to work on it in the very near future. But soon, hopefully in a month or two.

To view this discussion visit https://groups.google.com/d/msgid/projectchrono/b81c4d95-c531-4d4e-87a9-7efe794ee375n%40googlegroups.com.

[yueminzhang]

Thank you for your response.

We have recently encountered another new problem about SCM. When adding a fine-grained grid into the system, the redering efficiency would be low. Therefore, we need to perform a fine-grained grid only around the moving vehicle and other areas with low-resolution terrain, like the picture below. How can I achieve this effect?

Regards.

[Radu Serban]

I pushed a modification to SCMTerrain that will help you resolve this issue. Please see my reply in this thread: https://groups.google.com/g/projectchrono/c/kk0E0h4wrfs

--Radu

To view this discussion visit https://groups.google.com/d/msgid/projectchrono/CH3PPF46CDC218568AB4D0F90CAA1180108A7032%40CH3PPF46CDC2185.namprd06.prod.outlook.com.

[Radu Serban]

This adaptive refinement is not available in the new implementation of SCM (because it is not needed anymore for computational efficiency of the SCM calculations). As you noted, a very refined SCM grid may affect the rendering performance (if using the default visualization mesh which uses all SCM grid nodes). But that is an issue separate from the SCMTerrain computations. If you want to use a “lighter” visualization mesh, you will have to do this in your own code. You have access to all necessary data to control what and how is visualized, including the set of SCM grid nodes that were modified over the last time step; you can use those to decide how to update what you visualize.

 

--Radu

 

From: projec...@googlegroups.com <projec...@googlegroups.com> On Behalf Of yueminzhang
Sent: Wednesday, January 1, 2025 3:47 AM
To: ProjectChrono <projec...@googlegroups.com>
Subject: Re: [chrono] Help with SCMDeformableTerrain settings

 

Thank you for your response.

 

We have recently encountered another new problem about SCM. When adding a fine-grained grid into the system, the redering efficiency would be low. Therefore, we need to perform a fine-grained grid only around the moving vehicle and other areas with low-resolution terrain, like the picture below. How can I achieve this effect?

 

Regards.

To view this discussion visit https://groups.google.com/d/msgid/projectchrono/95f96dd3-3d1b-45c1-b18b-2c261de67b1bn%40googlegroups.com.