Geometry Preparation 

Our pugilist is based on Dolph Lundgren’s character Ivan Drago from Rocky 4. I was a child of the 80’s and adore boxing as a sport. The chosen character was Skyscraper, the iconic rig from the iAnimate course I took a few years back.

Let’s begin with the geometry. It really needs to have enough resolution to be able to crease, fold or wrinkle but not too dense or you’ll spend all your time waiting for results. We also want to start the modelling process with our character in the default bind pose and at world zero. This helps maintain a clean workflow and it will aid in the creation of the cloth rig we will be making later on.

We need a collider, this is often the body of the character, you want it to be a single mesh and have relatively low poly count. Often to help reduce computation time feel free to cut areas of the mesh that may not been needed. The facial features are normally an area where the collider can be simplified. Just remember that there maybe shot requirements that need the geometry that has been trimmed away, just be mindful.

We need geometry that we will become the nCloth object. Normally the workflow in CFX is to receive the geometry from the asset department but here we will make it ourselves. You don’t have to be a great modeler to be able to make sim geo. The basic shape of the structure is all you need. I usually create from the collider, extract the shape and go from there. I added more resolution to get those shorts to wrinkle. The mesh needs to be single sided and relatively clean. The output contains the detail and that will be wrapped to the finalling mesh, more on that in Rig Connections. Having a good UV map can come in useful.

As a final check we need to make sure it’s ready to be used in the rig, we need to do the following.

• Unlock Normals

• Soften Normals

• Freeze Transformations

• Delete History

This is something you’ll be doing for every single piece of geo in the cfx rig so this is a perfect candidate for a python script to automate these mouse clicks. Once it has been run you can save out the mesh as an Alembic.

You can by all means use a triangulated mesh for the collider and cloth meshes. The nCloth solver by default is set to triangulate, I usually leave this on. If you want to triangulate the geometry yourself there are a couple of ways to go about it. I like to use Houdini for the operation, here is a simple setup.

Houdini is a great tool, I’m still relatively new to it but I figure some of you guys maybe too. I use the alembic node to bring in the geo, object merge the selected parts inside a geometry node. The alembic will need to be unpacked before you can use it properly, this can be done using a unpack followed by a convert node. Add a remesh node and play with the target edge parameter, here it was set to 0.75. A rop output driver is used to export the geometry. An obj works with the non commercial version of Houdini so bear that in mind.

Be carefully with UVs when remeshing, I often UV the mesh before sending it to houdini for the remesh but if you didn’t you can use Maya’s Transfer Details option and use a worldspace transfer for the original quad geometry.