The Way - David Corral ( English Version)


( click on the image to enlarge )

David Corral Reel


Actually it was more a technical than an artistic concern. I contacted Alex Huguet several years ago through a common friend and told him to work together in a project and I started to work with his model Rhinoman who has got very interesting proportions.


In this specific case the inspiration was the real world. What I needed were muscle books, anatomy and bodybuilder videos to get exact references about the form and behavior of muscles depending on the body part.

Then you have to understand and simplify everything to apply into the CG. Nowadays it does not make sense a complete muscle system. The behavior is not going to be better than with simplified muscle system.

The technical inspiration was, above all, Fx films, with digital characters such as Hulk (2003) from ILM and also papers from Siggraph could give many ideas to face up a new project.

Artists like:

Erik Miller
Musculo-Skeletan Shape Skinning: Shape Skinning.pdf

Andreia Maiolo
Skinning in Maya at Industrial Light & Magic:

Paul Thuriot
Bulging Muscles and Sliding Skin: Deformation Systems for Hellboy:

I normally store huge amount of general documentation. You never know when you’re going to need it.


The techniques were about creating a muscle from a simple curve, and then attach it to the extremes of that curve, as in the real life. It is as fusiform muscle but with the difference that you get a non linear deformer as it is attached to a curve.

( click on the image to enlarge )

From the wire deformer of Maya I created a series of tools in order to work with it as it was a muscle, controlling its hardness, influence are on the skin, etc.

( click on the image to enlarge )

A part from the muscle system, I developed a system of PSD (Pose Space Deformer), in order to correct not accurate deformations.


The Animation character rig has got standard biped functions. It was on the deformations where I could innovate a bit.

( click on the image to enlarge )

At the beginning I started to make every muscle from fusiform, but I realized the behavior was not what I was expecting as the anchorage system was too basic. It’s very useful and it is ver fast to apply into a character, but the deformation is not as good as it should.

Creating muscles from curves made their behavior much more realistic. I only had to draw the curve where I wanted the muscle and make the skin of the skeleton to follow the character.

( click on the image to enlarge )

Calculating the length of the curve in a rest stage and comparing it with the actual stage I could give the value to the stretch/squash. Then I painted the deformer weights in the desired area getting the muscular effect on the skin. Although the effect of the deformer does not allow sliding you can simulate this effect later with corrective shapes.

( click on the image to enlarge )

In order to optimize the deformer’s speed I created a small script to which calculates the influence of the deformer according to the distance between a vertex and the curve.

( click on the image to enlarge )

Once the muscle deformers were created, instead of creating a tool of mirror for the weights (it’s usually a very slow process even with API), I used the skincluster mirror weights, which is very fast.

What I did was:

- Get the deformer’s weights, apply them to temporary mesh and bones and make a mirror weights to those temporary bones.

- Once I had those temporary weights already in the mirror, I only had to apply them to the mirror deformer and erase the temporary objects.

( click on the image to enlarge )

( click on the image to enlarge )

For the PSD I created two utilities. In one hand the blendshape releaser, which was a cone giving the influence area made of Maya nodes.

( click on the image to enlarge )

On the other hand I created a plug-in with Maya Python API in order to extract the blendshape corrector calculating the difference between each vertex local coordinates, the modeled mesh and the deformed mesh.

( click on the image to enlarge )

Once the blendshape corrector is extracted I only had to connect it to the blendshape releaser.


Most of times I work with cartoon characters as it is the most common thing I am asked to do for advertising, series, etc. So I can't work always on the stuff I would like to work on, that doesn't mean I don't like to work with cartoon characters, but I really like to work with realistic and fantastic characters. And I mean fantasty because I think it's an error to try simulate a real actor with CG.

( click on the image to enlarge )

( click on the image to enlarge )

That is the reason for using all my spare time learning this.


Thanks David for your participation in our blog!