Skip to content

[Mass] Introduce element-agnostic FEM mass#6061

Open
alxbilger wants to merge 18 commits intosofa-framework:masterfrom
alxbilger:femmass2
Open

[Mass] Introduce element-agnostic FEM mass#6061
alxbilger wants to merge 18 commits intosofa-framework:masterfrom
alxbilger:femmass2

Conversation

@alxbilger
Copy link
Copy Markdown
Contributor

@alxbilger alxbilger commented Mar 31, 2026

This PR adds a new finite-element mass implementation that builds a sparse global mass matrix from per-element quadrature, using nodal density values instead of a single uniform density.
It also introduces support for computing both kinetic and gravitational potential energy from that mass matrix, along with the corresponding force and matrix-assembly paths.
A new generic nodal-property abstraction was added so density can be stored per node and validated against the mechanical state’s scalar type.
The finite-element helpers were extended with shape-function evaluation and interpolation utilities needed for the mass integration.
The validation example was updated to use the new nodal-density-driven FEM mass setup.

[with-all-tests]


By submitting this pull request, I acknowledge that
I have read, understand, and agree SOFA Developer Certificate of Origin (DCO).


Reviewers will merge this pull-request only if

  • it builds with SUCCESS for all platforms on the CI.
  • it does not generate new warnings.
  • it does not generate new unit test failures.
  • it does not generate new scene test failures.
  • it does not break API compatibility.
  • it is more than 1 week old (or has fast-merge label).

@alxbilger alxbilger added pr: enhancement About a possible enhancement pr: status to review To notify reviewers to review this pull-request pr: highlighted in next release Highlight this contribution in the notes of the upcoming release labels Mar 31, 2026
@alxbilger alxbilger moved this to In Progress in Modular FEM mechanics Mar 31, 2026
@alxbilger
Copy link
Copy Markdown
Contributor Author

[ci-build][with-all-tests]

<MechanicalObject template="Vec3" name="state" showObject="true"/>

<MeshMatrixMass massDensity="1100" topology="@grid"/>
<NodalMassDensity property="1100"/>
Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I find the name Nodal* ambiguous since I wanted to rename some time ago the ConstantForceField and UniformMass respectively as NodalForceField and NodalMass

To me Nodal is inducing the absence of space integration

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In that case, there is no space integration. The density is really defined only on nodes.

}

template <class TDataTypes, class TElementType>
void ElementFEMMass<TDataTypes, TElementType>::validateNodalMassDensity()
Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This could have integrated a check on non-negative values

{

template<class T>
class BaseNodalProperty : public virtual sofa::core::objectmodel::BaseComponent
Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I would need some clarification on this BaseNodalProperty, would you like to extend it in the future for additional information?

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, mechanical parameters for example

Comment thread Sofa/Component/Mass/src/sofa/component/mass/ElementFEMMass.inl
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

pr: enhancement About a possible enhancement pr: highlighted in next release Highlight this contribution in the notes of the upcoming release pr: status to review To notify reviewers to review this pull-request

Projects

Status: In Progress

Development

Successfully merging this pull request may close these issues.

2 participants