3D Artist Bert Heynderickx - aka Alberto Ezzy - reveals how to create image maps for texturing skin and clothing using MARI and Photoshop in the second part of his tutorial series
See Part 1 of this tutorial series: Perfect the geometry of a male head
In Part 1 of this tutorial series we looked at the creation of a male head portrait in MODO, revealing how to use the Sculpt Tools in MODO to clean up the geometry of scanned head data, as well as adding and modifying a hat model to perfectly fit the character.
Now in Part 2, we will move on to use MARI and Photoshop to create the different image maps needed to feed the Skin Shader in MODO.
Step 1: Epidermis Diffuse Color Map
This is the main image map that is delivered with a scanned model from Ten24
. It's the base for almost all our other maps. I like to import this map into MARI and derive and paint other maps from it. This is quite a large map, so it's important to have a powerful graphics card, such as the AMD FirePro™ W9000
. Because of its large, dedicated memory and generous memory bandwidth (264 GB/sec) via the PCI 3.0, painting in MARI is incredibly smooth.
I select the first layer and rename it ‘Diffuse Color Map'. Right-click and select Import/Import into Layer. To be able to import images in MARI; the file has to have a certain naming convention. So you have to rename it to something like 'Skin.color.1001.tif'. According to the UV offset system in MARI, called ‘UDIM', this is the first ‘tile' in the UV grid. The '1001' refers to the first position the map needs the be in UV space.
Now, with this image imported and applied onto the model, let's paint away the parts of the hair cap that might be peeking from under the hat. For this, I select the Clone Stamp tool. It lets you copy parts from your image to the surface of your model. First you set a source point by CTRL+LMB (Control Button + Left Mouse Button). Then you can clone just like you would in an application such as Photoshop. I clone parts of the hair over the border of the cap.
This is the original diffuse map
Here we have the diffuse map loaded in MARI
Using the Clone Stamp in MARI
Covering the cap border with hair
The base for all our other skin maps, exported from MARI
Step 2: Epidermis SS Color Map
The Skin Material in MODO has 3 different layers: an Epidermal layer, an Upper Dermal layer and a Lower Dermal layer. First let's make an image map for the Epidermal layer.
To keep things organized, I copy the Color Channel in MARI and rename it ‘epidermis'. Now I need to desaturate the base Diffuse Color map. So I add an Adjustment Layer and choose HSL (Hue-Saturation-Light). I lower the Saturation to about 0.600. Next I add a Layer Mask and, with the color black, I paint a mask to recover a bit of Saturation on the ears and eyes of the model.
I like to use the Supersoft Brush Preset for this kind of work. The only thing left to do now is to export this result as a flattened image map for use in MODO. So right-click on the ‘epidermis' channel and choose Export Flattened>Export Current Channel Flattened.
Painting an adjustment layer mask in MARI
The Epidermis SS Color Map exported from MARI
Step 3: Upper Dermis SS Color
Next let's make the image map for the Upper Dermal layer. I copy the Color Channel in MARI and rename it ‘upper dermis'. This map has to have a nice fleshy pink tone, and some increased contrast.
To add some contrast to the base Diffuse Color map, I add a Contrast Adjustment Layer and set it to about 1.300. Next I desaturate it a bit with a HSL Adjustment Layer at 0.750 for the Saturation slider.
I add a fourth layer and change the Foreground Color to a fleshy pink and select Patch>Fill>Foreground to fill the whole layer with this chosen color. I set this color layer to Multiply at 0.500 to combine it with the underlying layers.
Then I add a mask to mask out the eyes, brows and hair so they don't get the pink tint. Last step is to export the flattened channel as described in the previous step.
Painting an adjustment layer mask in MARI
The Upper Dermis SS Color Map exported from MARI
Step 4: Lower Dermis SS Color
Next, let's make the image map for the Lower Dermal layer. I copy the Color Channel - which holds our base unaltered map - once again, and rename it ‘lower dermis'. This map has to have a reddish tone and quite some increased contrast. This is achieved by adding a Contrast and a Levels Adjustment Layer.
Notice that this is a completely non-destructive workflow. Whenever I feel necessary, I can change the values of these Adjustment Layers or even toggle them off to get back to my base, unaltered image map.
Applying adjustment layers in MARI
The Lower Dermis SS Color Map exported from MARI