From f4a9b24d6f87a1e92028f7082d9d7694dec2cd49 Mon Sep 17 00:00:00 2001
From: Paul Baksic <paul.baksic@outlook.fr>
Date: Tue, 16 Jun 2026 17:03:28 +0200
Subject: [PATCH 1/3] Use CCD for example scene

---
 examples/Demos/fallingSOFA.scn | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/examples/Demos/fallingSOFA.scn b/examples/Demos/fallingSOFA.scn
index d0a35dd5fa6..776962d885f 100644
--- a/examples/Demos/fallingSOFA.scn
+++ b/examples/Demos/fallingSOFA.scn
@@ -47,9 +47,8 @@
     <!-- This set the model used for contact behavior as Colomb's friction contact law using Lagrangian-based constraints -->
     <CollisionResponse name="ContactManager" response="FrictionContactConstraint" responseParams="mu=0.3" />
     <!-- This object is responsible for defining pairs of points used for contact simulation.
-    Alarm distance and contact distance are key parameters: alarm distance is the distance at which the collision
-    detection is being performed. The contact distance increases the contact distance between object, enforcing a 'skinning' behavior -->
-    <NewProximityIntersection name="Intersection" alarmDistance="0.02" contactDistance="0.002" />
+    The contact distance increases the contact distance between object, enforcing a 'skinning' behavior -->
+    <CCDTightInclusionIntersection name="CCDTightInclusionIntersection" continuousCollisionType="FreeMotion" maxIterations="100" contactDistance="0.00001"/>
 
     <!-- Non-simulated node used to create underlying deformable topology -->
     <Node name="BeamDomainFromGridTopology">
@@ -95,7 +94,7 @@
 
             <!-- This uses triangles as colliding element. These triangular primitives are the triangles present in the topology
             For more information on collision models see : https://sofa-framework.github.io/doc/components/collision/geometry/collisionmodels/ -->
-            <TriangleCollisionModel name="Collision" contactDistance="0.001" color="0.94117647058824 0.93725490196078 0.89411764705882" />
+            <PointCollisionModel name="Collision" contactDistance="0.0" color="0.94117647058824 0.93725490196078 0.89411764705882" />
 
             <!-- This is a mapping: it relates the position of this node to the one of the simulated node.
             The position of this node (the output of the mapping) is totally defined by the position of the input node
@@ -157,6 +156,6 @@
                                                  4 5 6  4 6 7" />
         <MechanicalObject template="Vec3"/>
         <!-- Because it is neither simulated nor moving, we can speed the solver and collision detection by setting parameters moving="0" simulated="0" -->
-        <TriangleCollisionModel name="CubeCM" contactDistance="0.001" moving="0" simulated="0" />
+        <TriangleCollisionModel name="CubeCM" contactDistance="0.00001" moving="0" simulated="0" />
     </Node>
 </Node>

From f558a143094e81e2a863b6be88ef22d91e2353a4 Mon Sep 17 00:00:00 2001
From: bakpaul <paul.baksic@outlook.fr>
Date: Fri, 19 Jun 2026 11:10:12 +0200
Subject: [PATCH 2/3] Remove warning and update comments

---
 examples/Demos/fallingSOFA.scn | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/examples/Demos/fallingSOFA.scn b/examples/Demos/fallingSOFA.scn
index 776962d885f..ff1b84569d3 100644
--- a/examples/Demos/fallingSOFA.scn
+++ b/examples/Demos/fallingSOFA.scn
@@ -47,8 +47,10 @@
     <!-- This set the model used for contact behavior as Colomb's friction contact law using Lagrangian-based constraints -->
     <CollisionResponse name="ContactManager" response="FrictionContactConstraint" responseParams="mu=0.3" />
     <!-- This object is responsible for defining pairs of points used for contact simulation.
-    The contact distance increases the contact distance between object, enforcing a 'skinning' behavior -->
-    <CCDTightInclusionIntersection name="CCDTightInclusionIntersection" continuousCollisionType="FreeMotion" maxIterations="100" contactDistance="0.00001"/>
+    Alarm distance and contact distance are key parameters: alarm distance is the distance at which the collision
+    detection is being performed. The contact distance increases the final distance between object, enforcing a 'skinning' behavior.
+    Here, because we are using CCD collision detection, the alarm distance can be set to 0-->
+    <CCDTightInclusionIntersection name="CCDTightInclusionIntersection" continuousCollisionType="FreeMotion" maxIterations="100" alarmDistance="0.0" contactDistance="0.00001"/>
 
     <!-- Non-simulated node used to create underlying deformable topology -->
     <Node name="BeamDomainFromGridTopology">
@@ -92,7 +94,7 @@
             <Tetra2TriangleTopologicalMapping input="@../Container" output="@Container" flipNormals="false"/>
             <MechanicalObject name="dofs" rest_position="@../mstate.rest_position"/>
 
-            <!-- This uses triangles as colliding element. These triangular primitives are the triangles present in the topology
+            <!-- This uses points as colliding element. These primitives are the one of the surface, thanks to the topological mapping
             For more information on collision models see : https://sofa-framework.github.io/doc/components/collision/geometry/collisionmodels/ -->
             <PointCollisionModel name="Collision" contactDistance="0.0" color="0.94117647058824 0.93725490196078 0.89411764705882" />
 

From f01745f6484500327d7a2afa0c47b00afc015ea2 Mon Sep 17 00:00:00 2001
From: bakpaul <paul.baksic@outlook.fr>
Date: Fri, 19 Jun 2026 11:24:54 +0200
Subject: [PATCH 3/3] Apply changes to simple-API based example

---
 examples/SimpleAPI/fallingSOFA.cpp | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/examples/SimpleAPI/fallingSOFA.cpp b/examples/SimpleAPI/fallingSOFA.cpp
index 24ed0ef3b42..93d7cc7d367 100644
--- a/examples/SimpleAPI/fallingSOFA.cpp
+++ b/examples/SimpleAPI/fallingSOFA.cpp
@@ -57,9 +57,11 @@ sofa::simulation::Node::SPtr createScene(const sofa::simpleapi::Simulation::SPtr
     sofa::simpleapi::createObject(root, "CollisionResponse",{{"name","ContactManager"},
                                                               {"response","FrictionContactConstraint"},
                                                               {"responseParams","mu=0.3"}});
-    sofa::simpleapi::createObject(root, "NewProximityIntersection",{{"name","Intersection"},
-                                                                     {"alarmDistance","0.02"},
-                                                                     {"contactDistance","0.002"}});
+    sofa::simpleapi::createObject(root, "CCDTightInclusionIntersection",{{"name","CCDTightInclusionIntersection"},
+                                                                     {"continuousCollisionType","FreeMotion"},
+                                                                     {"maxIterations","100"},
+                                                                     {"alarmDistance","0.0"},
+                                                                     {"contactDistance","0.00001"}});
 
     //Simulated Topology creation node
     const sofa::simulation::Node::SPtr BeamDomainFromGridTopology = sofa::simpleapi::createChild(root,"BeamDomainFromGridTopology");
@@ -83,7 +85,7 @@ sofa::simulation::Node::SPtr createScene(const sofa::simpleapi::Simulation::SPtr
     sofa::simpleapi::createObject(FEMechanicalModel_Surface, "TriangleSetTopologyModifier", {{"name","Modifier"}});
     sofa::simpleapi::createObject(FEMechanicalModel_Surface, "Tetra2TriangleTopologicalMapping", {{"input","@../Container"}, {"output","@Container"}, {"flipNormals","false"}});
     sofa::simpleapi::createObject(FEMechanicalModel_Surface, "MechanicalObject", {{"name","dofs"},{"rest_position","@../mstate.rest_position"}});
-    sofa::simpleapi::createObject(FEMechanicalModel_Surface, "TriangleCollisionModel", {{"name","Collision"},{"proximity","0.001"}, {"color","0.94117647058824 0.93725490196078 0.89411764705882"}} );
+    sofa::simpleapi::createObject(FEMechanicalModel_Surface, "PointCollisionModel", {{"name","Collision"}, {"color","0.94117647058824 0.93725490196078 0.89411764705882"}} );
     sofa::simpleapi::createObject(FEMechanicalModel_Surface, "IdentityMapping", {{"name","SurfaceMapping"}});
 
     const std::vector<std::string > visuFiles{"mesh/SofaScene/LogoVisu.obj", "mesh/SofaScene/SVisu.obj", "mesh/SofaScene/O.obj", "mesh/SofaScene/FVisu.obj", "mesh/SofaScene/AVisu.obj"};
@@ -105,7 +107,7 @@ sofa::simulation::Node::SPtr createScene(const sofa::simpleapi::Simulation::SPtr
                                                                           {"position","0.2 0 -0.5  0.2 0.1 -0.5  0.3 0.1 -0.5  0.3 0 -0.5  0.2 0 -0.6  0.2 0.1 -0.6  0.3 0.1 -0.6  0.3 0 -0.6"},
                                                                           {"triangles","0 2 1  0 3 2  0 1 5  0 5 4  0 4 7  0 7 3  1 2 6  1 6 5  3 7 6  3 6 2  4 5 6  4 6 7"}} );
     sofa::simpleapi::createObject(Floor, "MechanicalObject", {{"template","Vec3"}});
-    sofa::simpleapi::createObject(Floor, "TriangleCollisionModel", {{"name","FloorCM"}, {"proximity","0.001"}, {"moving","0"}, {"simulated","0"}} );
+    sofa::simpleapi::createObject(Floor, "TriangleCollisionModel", {{"name","FloorCM"}, {"contactDistance","0.00001"}, {"moving","0"}, {"simulated","0"}} );
     return root;
 }