Mesh Deform:
Proxy Physics:
My normal method of proxy physics, uses the mesh deform modifier with a three point flow.
IE-
Physics Mesh -> Transformation Mesh -> Render Mesh
Each mesh is connected using the Mesh Deform Modifier.
The Mesh Deform modifier ignores non generative modifiers on the target mesh. However, the target mesh can be changed after the binding is complete.
Even though the target mesh is greyed out, just click on it and set it to your true target mesh.
Note that the new and old target mesh must have the same vertices with the same index. Typically speaking, this means the binding target must be a copy of the true target.
This method allows this workflow:
Copy Transformation Mesh -> Apply all modifiers on the copy -> Bind Render Mesh to Copy -> Switch Mesh Target from the copy to the original
Okay, so why would you want to do this? There are many reasons, but the most common one is that often, the physics mesh looks different than the Render mesh. Placing a solidify modifier, followed by a displace modifier, and other modifiers as needed, allows the transformation mesh to be shaped to encompass the render mesh.
Another useful thing to note- Adding or deleting faces and edges has no effect on vertex index. Thus, unwanted faces can be removed. If a vertex isn’t wanted during binding, simply leave it “floating” unconnected to any face or edge.
This is particularly important regarding Physics -> Transformation binding, when the physics mesh contains large amounts of “strange” faces. When creating the physics mesh, use a special material and mark all “strange” faces. During binding, delete all “strange” faces. What do I mean by “strange”? Normally anything not manifold, except boundaries.
A useful note- Make sure not to accidentally delete a vertex while deleting edges and faces.
A useful note- If you have a solidify modifier on a mesh and its copy, you can still delete any number of faces or edges before applying the modifier, and the vertex indexes will still match.
Normally, my Transformation Mesh, is, originally, a copy of my physics mesh. It has all the same vertices in all the same locations. This allows a certain trick to, under almost all circumstances, successfully bind the Transformation Mesh to the Physics Mesh.
The workflow is:
Give Physics Mesh a Solidify modifier followed by a displace modifier.
Copy Physics Mesh
Remove unwanted faces from copy.
Apply all modifiers to copy.
Bind Transformation Mesh to Copy
Switch Bind to Original
Solidify and Mesh Deform are a match made in heaven. In particular, the solidify modifier is the key to using mesh deform with non manifold topology, as is the case in most cloth physics simulations.
Cloth Physics:
Resuming Simulation:
To resume a simulation, from the middle of a simulation, my procedure is:
Free Bake
Place the timeline on the desired frame.
Hide Cloth Physics modifier
Unhide Cloth Physics modifier
Enable Disk Cache
Go to the folder containing the generated results. Rename the folder. Remember the original name.
Place the timeline on the initial frame.
Copy the contents from the renamed folder to a new folder with the same name as the original folder. (You can simply rename the folder back to its original name, but I’ve accidentally deleted my simulation results by doing so.)
Disable Disk Cache
Using Shape Keys:
A physics simulation will always judge the mesh using the first frame of the simulation. Sometimes, the desired initial position of the mesh is different from the desired judgement position. For instance, imagine a belt, that is supposed to cling to a character’s waist.
If I wanted to achieve this I would-
Create a circle. Extrude, move negative on Z axis
Create a shape key. Select it.
Select top and bottom edge loops. Set pivot points to individual origins. Scale until the edges are inside the collision (character’s) mesh.
Create two vertex groups- Root, and All
Assign all vertices to All
Add modifier- Vertex Weight Mix
Vertex Group A = Root
Vertex Group B = All
Mix Mode = Add
Mix Set = All
Set Frame to 3
Insert Keyframe: Unhide Vertex Weight Mix Modifier
Set Frame to 4
Insert Keyframe: Hide Vertex Weight Mix Modifier
Set Frame to 2
Insert Keyframe: Shapekey value 0
Set Frame to 1
Insert Keyframe: Shapekey value 1
Add Cloth Physics Modifier. Enable Pinning. Set Pinning group to Root
Using Hyper Cubes:
A hyper cube, in the instance refers to a certain shape, wherein additional faces are added to the interior of a cubelike object to aid in physics simulation. Hyper cubes are generally used when it becomes necessary to simulate rigid objects with cloth physics. Blender has a good rigid object simulator, but it is not ideal for rigid objects attached to non-rigid objects. For instance, a pendant on a necklace.
Some of my meshes contain large quantities of hyper cubes. Rather than placing each face manually it became imperative to generate them quickly.
My procedure is as follows-
Duplicate physics mesh
Select all edges. Mark Sharp. Deselect all.
For each cubelike, select one face.
Set pivot points to individual origins. Scale to -1
Assign Selected to Vertex Group
Leave Edit Mode, Add Edge Split modifier, apply
Reenter Edit Mode, use edge selection mode
Select Vertex Group
Scale to -1
select all, remove doubles
Select top and bottom faces, delete
Select All
Set face material to Material B (To a distinct material)
Join duplicate with original
Select All
Remove Doubles
If desired, create 2 copies instead of 1. For each cubelike on the copy, select one of the faces connected to the face you first selected, then follow the procedure as above. This will create a perfect symmetric hypercube.