This ‘making of’ tutorial covers how to deform a head model into a surreal shape using the L3 Deformer plugin from Lightstorm3D (purchase required). This toolset is a collection of advanced deformation nodes and utilities for Maya. We will focus on the Collision Deformer in this tutorial. We will then move onto shading and lighting the head model to create a convincing photographic portrait look to our render. We will use the alSurface shader to add skin shading to the model with Arnold. Arnold can make use of 3rd party shaders such as the alShaders by Anders Langlands. This collection of shaders will need to be installed prior to starting this tutorial. Further examples using this technique can be found here.
This tutorial is divided into the following sections:
- Deforming the Head
Head scan deformed using various Collider shapes such as spheres and cubes
|Before you start this tutorial ensure that you have downloaded and installed the following files:|
Make sure that the L3 Deformer plugin is installed correctly and loaded in the Maya Plug-in Manager before starting this tutorial.
The Collision Deformer allows you to collide objects with polygon geometry, using projected collisions such as directional, concentrical and cylindrical.
- Start off by opening the head model.
- Create a polygon cube and position it roughly in the same position as in the image below. Bevel the edges of the cube. This will give a softer edge to the head deformation effect.
Bevelled polygon cube positioned around head model
- Select the head geometry and go to Lightstorm3D> Deformer> Collision Deformer> Create Collision Deformer. Change the Collision Deformer name to ‘Head’ and click on Create Collision Deformer.
- It is possible to increase the Envelope above 1 to exaggerate the deformation effect. In this case a maximum value of 2 has been used. You can also disable Mesh Relaxing as this won’t be necessary for such a simple cube shape.
Collision Deformer settings
The Collider node comes with some extra attributes aside from specifying the type of projection. You can choose between inward and outward projection for concentrical and cylindrical projections. You can also specify which side of a polygon to consider during collision detection (frontal, posterior or both). Soft depth and resistance attributes simulate the effect of soft collision geometry that can be compressed to some degree.
In this tutorial we will use the default concentrical collider setting, but we will alter the Soft depth and resistance values to achieve a smoother deformation effect.
- Select the cube geometry and go to Lightstorm3D> Deformer> Collision Deformer> Create Collider. Choose Head from the Deformer List and click on Create Collider.
Head geometry ‘colliding’ with cube geometry using the default settings
The deformation effect currently looks too angular. We will need to change some of the default Collision Settings to give a softer merge between the head and the cube.
- Reduce the Soft Depth to around 0.1 and the Soft Resistance to around 0.05. Reducing the Weight slightly also helps to ‘soften’ the collision effect.
Adjusting the Collider Settings gives a softer collision effect
|Remember to convert your textures to .tx format using the TX Manager for more efficient rendering. You should use .tx files for everything (except with the aiSkydome and Quad lights).|
- Assign an alSurface shader to the head model. Change its Preset to als_Skin to give you a good looking skin preset to start off with.
- Connect the head color map to the Diffuse Color and SSS Radius color attributes. Change the SSS Mix to around 0.4 (0 means no SSS, full diffuse. 1 means full SSS no diffuse).
- Increase the SSS Density Scale to around 40 (depending on the scale of the model). Higher values mean a larger and a harder looking SSS. Lower values mean smaller and a more softer looking SSS.
- Connect the normal map file to the Bump map attribute. Change it to use Tangent Space Normals.
- Connect the specular map to the Specular 1 Color attribute. Reduce the Specular Strength to 0.1 and the Specular Roughness to 0.1.
alSurface shader skin settings
Below you can see the difference when rendering with the SSS modes: Cubic and Directional. The difference is subtle, but Directional SSS is generally recommended for skin as it has less of a ‘waxy’ appearance.
SSS Mode: ‘Cubic’ (looks too waxy) vs ‘Directional’ (recommended for skin).
- Create an aiSkyDome light and connect a file texture to the Color attribute. Open the hdr map below in the file texture.
- Change the format of the aiSkyDome light to mirrored_ball to match the hdr format above.
- The overall lighting looks a bit flat with just the aiSkyDome light. We can add some more focused, directional lighting to the head model. Create two cylinder lights and place them above (in front and behind) the model. Enable Use Color Temperature for the cylinder lights and change the Temperature to around 5000 to give a warmer look to the scene lighting.
aiSkydome light only looks flat (left).aiSkydome light with cylinder lights (right) looks more interesting.
Final scene lighting. aiSkyDome light with two aiArea cylinder lights
For final rendering increase all light Samples to 3 and increase Camera (AA) to 5 or 6. The SSS looks a little noisy with SSS Mode set to Directional using the default settings. Try increasing the SSS to 3 or 4 for the final render. Beware that increasing SSS samples can have a large impact on render time.
SSS Samples 2 (left). SSS Samples 4 (right).
Applying Auto Tone to the image in Photoshop adjusts the tonal values and gives a more pleasing ‘photographic’ look to the render. Remember to convert the image to 8-bit prior to using Auto Tone.
Before ‘Auto Tone’ (left). After ‘Auto Tone’ (right).
That concludes this making of tutorial. Why not have a go at producing some bizarre and surreal head shapes using this technique!