Fixes to re-enable backwards compatibility (#577)

# Description

Some fixes for running latest Isaac Lab updates with Isaac Sim 4.5.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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source/isaaclab/isaaclab/assets/articulation/articulation.py

@@ -1274,6 +1274,11 @@ class Articulation(AssetBase):
             spatial_tendon_ids: The tendon indices to set the stiffness for. Defaults to None (all spatial tendons).
             env_ids: The environment indices to set the stiffness for. Defaults to None (all environments).
         """
+        if int(get_version()[2]) < 5:
+            omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0. Please update to Isaac Sim 5.0 or later."
+            )
+            return
         # resolve indices
         if env_ids is None:
             env_ids = slice(None)
@@ -1300,6 +1305,11 @@ class Articulation(AssetBase):
             spatial_tendon_ids: The tendon indices to set the damping for. Defaults to None (all spatial tendons).
             env_ids: The environment indices to set the damping for. Defaults to None (all environments).
         """
+        if int(get_version()[2]) < 5:
+            omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0. Please update to Isaac Sim 5.0 or later."
+            )
+            return
         # resolve indices
         if env_ids is None:
             env_ids = slice(None)
@@ -1326,6 +1336,11 @@ class Articulation(AssetBase):
             spatial_tendon_ids: The tendon indices to set the limit stiffness for. Defaults to None (all spatial tendons).
             env_ids: The environment indices to set the limit stiffness for. Defaults to None (all environments).
         """
+        if int(get_version()[2]) < 5:
+            omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0. Please update to Isaac Sim 5.0 or later."
+            )
+            return
         # resolve indices
         if env_ids is None:
             env_ids = slice(None)
@@ -1352,6 +1367,11 @@ class Articulation(AssetBase):
             spatial_tendon_ids: The tendon indices to set the offset for. Defaults to None (all spatial tendons).
             env_ids: The environment indices to set the offset for. Defaults to None (all environments).
         """
+        if int(get_version()[2]) < 5:
+            omni.log.warn(
+                "Spatial tendons are not supported in Isaac Sim < 5.0. Please update to Isaac Sim 5.0 or later."
+            )
+            return
         # resolve indices
         if env_ids is None:
             env_ids = slice(None)
@@ -1504,8 +1524,8 @@ class Articulation(AssetBase):
             self._data.default_joint_friction_coeff = (
                 self.root_physx_view.get_dof_friction_coefficients().to(self.device).clone()
             )
-            self._data.default_joint_dynamic_friction_coeff = None
-            self._data.default_joint_viscous_friction_coeff = None
+            self._data.default_joint_dynamic_friction_coeff = torch.zeros_like(self._data.default_joint_friction_coeff)
+            self._data.default_joint_viscous_friction_coeff = torch.zeros_like(self._data.default_joint_friction_coeff)
         else:
             friction_props = self.root_physx_view.get_dof_friction_properties()
             self._data.default_joint_friction_coeff = friction_props[:, :, 0].to(self.device).clone()
@@ -1519,12 +1539,8 @@ class Articulation(AssetBase):
         self._data.joint_damping = self._data.default_joint_damping.clone()
         self._data.joint_armature = self._data.default_joint_armature.clone()
         self._data.joint_friction_coeff = self._data.default_joint_friction_coeff.clone()
-        if int(get_version()[2]) < 5:
-            self._data.joint_dynamic_friction_coeff = None
-            self._data.joint_viscous_friction_coeff = None
-        else:
-            self._data.joint_dynamic_friction_coeff = self._data.default_joint_dynamic_friction_coeff.clone()
-            self._data.joint_viscous_friction_coeff = self._data.default_joint_viscous_friction_coeff.clone()
+        self._data.joint_dynamic_friction_coeff = self._data.default_joint_dynamic_friction_coeff.clone()
+        self._data.joint_viscous_friction_coeff = self._data.default_joint_viscous_friction_coeff.clone()
 
         # -- body properties
         self._data.default_mass = self.root_physx_view.get_masses().clone()

source/isaaclab/isaaclab/sim/simulation_context.py

@@ -140,6 +140,10 @@ class SimulationContext(_SimulationContext):
         # acquire settings interface
         self.carb_settings = carb.settings.get_settings()
 
+        # read isaac sim version (this includes build tag, release tag etc.)
+        # note: we do it once here because it reads the VERSION file from disk and is not expected to change.
+        self._isaacsim_version = get_version()
+
         # apply carb physics settings
         self._apply_physics_settings()
 
@@ -217,9 +221,6 @@ class SimulationContext(_SimulationContext):
         # ref: https://docs.omniverse.nvidia.com/prod_extensions/prod_extensions/ext_physics.html
         # note: need to do this here because super().__init__ calls render and this variable is needed
         self._fabric_iface = None
-        # read isaac sim version (this includes build tag, release tag etc.)
-        # note: we do it once here because it reads the VERSION file from disk and is not expected to change.
-        self._isaacsim_version = get_version()
 
         # create a tensor for gravity
         # note: this line is needed to create a "tensor" in the device to avoid issues with torch 2.1 onwards.
@@ -344,8 +345,11 @@ class SimulationContext(_SimulationContext):
                 )
 
             # parse preset file
-            repo_path = os.path.join(carb.tokens.get_tokens_interface().resolve("${app}"), "..")
-            preset_filename = os.path.join(repo_path, f"apps/rendering_modes/{rendering_mode}.kit")
+            # check if using isaac sim 4.5 and adjust path accordingly
+            repo_path = os.path.join(carb.tokens.get_tokens_interface().resolve("${app}"))
+            if self._isaacsim_version[0] == 4 and self._isaacsim_version[1] == 5:
+                repo_path = os.path.join(repo_path, "isaacsim_4_5")
+            preset_filename = os.path.join(repo_path, f"rendering_modes/{rendering_mode}.kit")
             with open(preset_filename) as file:
                 preset_dict = toml.load(file)
             preset_dict = dict(flatdict.FlatDict(preset_dict, delimiter="."))

source/isaaclab/test/assets/test_articulation.py

@@ -22,6 +22,7 @@ import torch
 
 import isaacsim.core.utils.prims as prim_utils
 import pytest
+from isaacsim.core.version import get_version
 
 import isaaclab.sim as sim_utils
 import isaaclab.utils.math as math_utils
@@ -1866,6 +1867,10 @@ def test_spatial_tendons(sim, num_articulations, device):
         num_articulations: Number of articulations to test
         device: The device to run the simulation on
     """
+    # skip test if Isaac Sim version is less than 5.0
+    if int(get_version()[2]) < 5:
+        pytest.skip("Spatial tendons are not supported in Isaac Sim < 5.0. Please update to Isaac Sim 5.0 or later.")
+        return
     articulation_cfg = generate_articulation_cfg(articulation_type="spatial_tendon_test_asset")
     articulation, _ = generate_articulation(articulation_cfg, num_articulations, device=device)
 
@@ -1922,8 +1927,9 @@ def test_write_joint_frictions_to_sim(sim, num_articulations, device, add_ground
     dynamic_friction = torch.rand(num_articulations, articulation.num_joints, device=device)
     viscous_friction = torch.rand(num_articulations, articulation.num_joints, device=device)
     friction = torch.rand(num_articulations, articulation.num_joints, device=device)
-    articulation.write_joint_dynamic_friction_coefficient_to_sim(dynamic_friction)
-    articulation.write_joint_viscous_friction_coefficient_to_sim(viscous_friction)
+    if int(get_version()[2]) >= 5:
+        articulation.write_joint_dynamic_friction_coefficient_to_sim(dynamic_friction)
+        articulation.write_joint_viscous_friction_coefficient_to_sim(viscous_friction)
     articulation.write_joint_friction_coefficient_to_sim(friction)
     articulation.write_data_to_sim()
 
@@ -1933,8 +1939,9 @@ def test_write_joint_frictions_to_sim(sim, num_articulations, device, add_ground
         # update buffers
         articulation.update(sim.cfg.dt)
 
-    assert torch.allclose(articulation.data.joint_dynamic_friction_coeff, dynamic_friction)
-    assert torch.allclose(articulation.data.joint_viscous_friction_coeff, viscous_friction)
+    if int(get_version()[2]) >= 5:
+        assert torch.allclose(articulation.data.joint_dynamic_friction_coeff, dynamic_friction)
+        assert torch.allclose(articulation.data.joint_viscous_friction_coeff, viscous_friction)
     assert torch.allclose(articulation.data.joint_friction_coeff, friction)