[SOLVED] Unable to create ‘BilateralInteractionConstraint’

[Owen]

Hello SOFA community,

I encountered a problem when I was trying to use BilateralInteractionConstraint to attach one soft actuator to another. The error shown in the command line is below:

[ERROR]   [PythonScript] RuntimeError: Unable to create 'BilateralInteractionConstraint' of type 'BilateralInteractionConstraint' in node 'root'. Object type BilateralInteractionConstraint<Vec3d> was not created  
 The object is in the factory but cannot be created.  
Requested template: Vec3d(Vec3d)  
Available templates: Rigid3d, Vec3d,   

  File "Ex3Ex3.pyscn", line 165, in createScene
    rootNode.createObject('BilateralInteractionConstraint', template = "Vec3d", object1 = "@pneu1/Constraint/points", object2 = "@pneu2/Constraint/points", first_point = "1", second_point = "0")

In addition, the collision model doesn’t seem to work in my scene. I wonder if this is caused by the failure of using BilateralInteractionConstraint.

This is the link to my codes and CAD file:
https://drive.google.com/open?id=14upVfy_OBgSgKFw9lSF3u5NzMG8ZBI_A

The actuator is controlled by pressing “ctrl”+”-” and “ctrl”+”=” on the keyboard. After running the scene, the error should be easy to notice. I have spent a whole day on this issue… So any advice would be greatly appreciated!

Best,
Owen

[Hugo]

Hi @qwe12050

it took me some time to found because it’s very simple!
Check the case of your node “constraint” one is a “c” another is a “C”

Best

Hugo

[Binesh]

Hi @qwe12050
I checked your python codes and i think there is a problem in your code,
for creation of bilateral Interaction Constraint, you have to create a mechanical state same as bilateral template
i cannot see any mechanical state in your “rootNode”,
i think you must create a mechanical state in Vec3 Template

Best,

Behnam Binesh

[Owen]

Hi @secretdevil

Thank you for your reply!

I have corrected the case of “Constraint” as Hugo suggested, and then I don’t have this error anymore. I am sorry that my code is a bit messy… Even though I don’t fully understand how the templates work, I think the mechanical state was created in the children of rootNote. Like in Line 126 pneu2.createObject('MechanicalObject', name='tetras', template='Vec3d', showObject='0', showObjectScale='1') etc.

I guess for now I will move on since the error disappears. If I encounter similar problems again, I will examine my code and find where Vec3d is missing.

Best wishes,
Owen

[Hugo]

Nice @qwe12050
By the way it starts being a nice complicated scene, good to see that!
Good luck in the next steps and forum remains at your disposal!

Best,

Hugo

[Owen]

Hi @hugo,

I feel kinda stupid to waste your time on fixing this tiny error… However, I have one more question to ask about BilateralInteractionConstraint if you don’t mind. I found this page explaining the Args: https://sofacomponents.readthedocs.io/en/latest/_autosummary/_autosummary/sofacomponents.ConstraintSet.BilateralInteractionConstraint.html

But I still don’t understand what first_point and second_point represent. For example, in my case, I want to combine two objects so I created two points on the body of each object. What would my first_point and second_point be?

Best,
Owen

[Hugo]

Hi @qwe12050

Never feel this way, this forum is made for this! So use it as much as it can help you!

These vectors of integers respectively correspond to the indices of the object1 and object2 which you are about to constraint together.

Best wishes,

Hugo

[Author]

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