The `<attach>` element now supports a "frame" attribute, allowing users to specify either a "body" or a "frame" to attach to, but not both. The XML parser has been updated to handle this new attribute and the mutual exclusivity constraint.
PiperOrigin-RevId: 941245904
Change-Id: I4c0edeed5f3a9e456aed96c373b1647fe79841d9
For example when loading parent_merge.xml:
```
WARNING: Attach conflict when attaching 'child' to 'parent_merge', policy is 'merge'
timestep: parent has 0.005, child has 0.002, taking the minimum
iterations: parent has 50, child has 100, taking the maximum
flag 'Damper': added from child
```
When loading parent_error.xml:
```
XML Error: Attach conflict when attaching 'child' to 'parent_error', policy is 'error'
timestep: parent has 0.005, child has 0.002
iterations: parent has 50, child has 100
Element 'attach', line 10
```
PiperOrigin-RevId: 933620810
Change-Id: Ib477863b5ef763474d27fb4be5a4148be1d5d500
Each mjEQ_FLEXSTRAIN equality now represents a single cell within a flex. This allows for more efficient sparse Jacobian computation by only considering the degrees of freedom of the nodes within each specific cell. This change gives a speedup of about 10x on a 3x3x3 model.
PiperOrigin-RevId: 902164069
Change-Id: I78eedf1d5cf39b8989fe9863c22d164922fc0efb
This change introduces a `flex_cellcount` field to `mjModel` to specify the number of cells in each dimension for interpolated flexes. The stiffness computation, passive force calculation, and Jacobian derivatives are updated to operate on a per-cell basis, significantly improving performance by localizing computations to the nodes within each cell.
PiperOrigin-RevId: 901216393
Change-Id: Ic23132e609de11e71bb7fef8d1f139daad2ec264
The `vertcollide` attribute in flex and flexcomp contact specifications has been removed since the next mjWarp release will support flex collisions. This attribute was previously used to enable vertex-based collisions by adding sphere geoms at flex vertices. The functionality associated with this attribute has been deprecated and removed from the XML parser, documentation, and internal data structures. Affected example XML files have also been updated.
PiperOrigin-RevId: 885595503
Change-Id: I6a78975f1bc540c09ea8b5306ff3be0962b7ab24
This attribute allows specifying the intended output types (e.g., RGB, depth, normal) for each camera in the XML. The output types are stored as bit flags in `mjModel`.
PiperOrigin-RevId: 853316261
Change-Id: I1ad2e94102593cf402756f8f4c80509371ca86d2
This extends both the spec and the XML definition to allow specification of a material name on a mesh. This material acts as a fallback in the case that the referencing geom element does not specify a material of it's own.
PiperOrigin-RevId: 798232378
Change-Id: Iaf300c727732744ea1b613e64334ee505ac6e209
These flexes use only 24 DOFs (3 per vertex of the bounding box), while colliding with the full high resolution mesh.
On an 8x8x8 cube, the performance using DOFs at all vertices is
```
Simulation time : 18.74 s
Steps per second : 533
Realtime factor : 0.53 x
Time per step : 1874.4 µs
Contacts per step : 114.88
Constraints per step : 3322.51
Degrees of freedom : 1536
```
With the new implementation, it is the following:
```
Simulation time : 1.82 s
Steps per second : 5507
Realtime factor : 5.51 x
Time per step : 181.6 µs
Contacts per step : 38.84
Constraints per step : 155.36
Degrees of freedom : 24
```
PiperOrigin-RevId: 721008829
Change-Id: I833df027527db578d86667cc4b24295bcf6f7d22
Yuval Tassa