3D Artist
Apr
23

Create skin shaders in Blender and ZBrush

Tips & Tutorials
by
Gustavo Ahlen

Learn how to create an accurate clay sculpture in ZBrush and achieve realistic skin in Blender with this guide to sculpting elderly bodies


Create skin shaders in Blender and ZBrush

This tutorial was written by the amazing Gustavo Ahlen and appeared in issue 108 of 3D Artist. Subscribe today and never miss an issue!

Tools used

ZBrush
Blender
Photoshop

This tutorial covers techniques that will enhance your skills in sculpting elderly bodies in ZBrush and creating realistic skin shaders in Blender.

Using this step-by-step guide you’ll learn how to sculpt an old man in ZBrush. References for this kind of tutorial are essential to correctly sculpt the human body, helping you follow the correct proportions and general aspects.

You’ll learn a few tricks throughout this tutorial that will enable you to achieve realistic skin for characters quickly. With the inclusion of the Cycles render engine, Blender is an easy 3D software to use, with huge advantages when it comes to rendering speed. Materials have input nodes to control the curves of each texture according to the global lighting, where we can get a preview of the final render while adjusting the inputs. Let’s get started.

 

Step 01 – Average male mesh


Create skin shaders in Blender and ZBrush

Let’s start with adding the base mesh from Lightbox>Tool, selecting the file under the name MaleAverage.ZTL and deleting the Floor subtool. The process of using an average model previously sculpted will save you a lot of time, as we can just adapt this base model in accordance with our reference images. 

Step 02 – Use Floor Grid for references


Create skin shaders in Blender and ZBrush

There are a few methods to work with images of reference, but the most accurate is the use of Floor Grid. This method can be used by going to Draw and activating Floor. Below this option there are several menus, and for this work we used Front-Back and Left-Right. There you can see two slots where you should load your reference images. In each option, you can adapt this reference to the main model using Scale, Horizontal and Vertical Offset. Don’t forget to deactivate Perspective Distortion (P).

 

Step 03 – Adapt model to references


Create skin shaders in Blender and ZBrush

The base mesh should be adapted to the image of reference. This can be done using the Move brush. Following the reference, there are a few arrows that will determine where to pull and where to push. As the reference is smaller than the base mesh, try to use a large brush size to move the mesh, aiming to adapt it correctly. Guide your sculpture using the front and side view.
 

Step 04 – Block out low-res model


Create skin shaders in Blender and ZBrush

For sculpting a low-res base model, use ClayBuildup with Z Intensity values under 7, and with the help of the Smooth brush (Shift) you can smooth the sharp areas. Once you get something similar to the current image, increase the subdivision level to 2 or 3 but deactivate the Smt option (Subdivide Smooth Modifier). Now, using the Smooth brush you can smooth the whole model with more accurate results. We deactivated Smt because it can deform the fingers and other extremities. Now, turn this model into DynaMesh.
 

Step 05 – Build the leg musclesx


Create skin shaders in Blender and ZBrush

For defining the leg muscles we should use ClayBuildup and Clay Tubes to get an shape that’s similar to our references, and Dam_Standard to increase the muscle definitions. The basic method of sculpting muscles is following the muscle structure as you can see in the drawing. The orange strokes show you the limits of the muscle, the white strokes show the volume and the yellow strokes depict the stroke orientation of ClayBuildup. Once you get an approximation, use the Smooth brush to get a smooth definition of the skin.
 

Step 06 – Define the arm muscles


Create skin shaders in Blender and ZBrush

To sculpt the arm muscles, use Dam_Standard to enhance the separations between the muscles and ClayBuildup to increase the volume of the muscles. Try to follow the écorché reference images to understand the muscles insertions and origins. This is essential to understanding what we are doing.
 

Step 07 – Sculpt thorax muscles


Create skin shaders in Blender and ZBrush

In the current image, we merged the final sculpture with an écorché reference. This will help you to know where you should use Dam_Standard and where you should use ClayBuildup. Once you reach a similar sculpture to what can be seen on the left, use the Smooth brush to get an accurate sculpture.
 

Step 08 – Define face muscles


Create skin shaders in Blender and ZBrush

The facial skin of elderly men is loose, like other areas of the body. This sculpting should be done using ClayBuildup, Clay Tubes,
Move and Smooth. Dam Standard is useful to enhance the separation between muscles as we have done previously. To achieve loose, hanging skin, we can use Move to pull and push some areas of the face like the chin and neck.
 

Step 09 – Sculpt finger/toenails


Create skin shaders in Blender and ZBrush

For sculpting the nails we can use a common method highly useful for this kind of work. Mask the sculpture with Ctrl+Left Click (over the viewport). Now, the areas of the nails should be unmasked using Ctrl+Alt+Left Click. Once you have unmasked these areas, select Move (W) and move the unmasked areas as you can see in the current image. Try to do this process individually, not all at once.
 

Step 10 – Facial muscle structure


Create skin shaders in Blender and ZBrush

The muscle structure is represented by the white lines. The arrows show you how the brush should slide over the mesh. It is like sculpting a cylinder or a curved area. If you hold Alt you can remove the excess of clay, like with a pottery tool. Once you get an approximation tofo the references, simply hold Shift to smooth the sculpture. Now using Dam_Standard we can enhance the wrinkles as muscle separations.
 

Step 11 – Polygroups and UV maps


Create skin shaders in Blender and ZBrush

For creating UV maps, first duplicate the Body subtool. Now, using ZRemesher, try to get 15K poly at the lower resolution level (SDiv 1). Now, Divide the new cleaned mesh (SDiv 2) and using Subtool> Project, you can retrieve the details from the original mesh. Do this until the higher subdiv level of the new mesh reaches the higher subdiv level of the original mesh. In the new mesh, go back to the first SDiv 1, and separate the body in different polygroups as per the reference. Use UV Master to unwrap
the model.
 

Step 12 – Polypaint skin shader


Create skin shaders in Blender and ZBrush

Start using skin tones with a RGB intensity under 50. Keep a soft and blurry overall look for the skin base. We recommend using a Standard brush with Color Spray and Alpha 47. Try to use the C hotkey to sample colours on your canvas, keeping the skin tones. To add
small details, just load a skin texture and use the DragRect stroke to paint the loaded textures. Keep in mind that Polypaint
is flat, and to get a better volume of what we are painting we should use a base material with Specularity as SkinShade4.
 

Step 13 – Import OBJ mesh in Blender


Create skin shaders in Blender and ZBrush

Open Blender and go to File>Import and load the OBJ. This will import the OBJ file in separated polygroups (Groups). Don’t worry about
this because when you do a click over each group, you will reveal the separations we made previously in ZBrush.
 

Step 14 – Skin shader material


Create skin shaders in Blender and ZBrush

For the skin shader material, go to the Outliner panel. Click in one group and click on the small material icon. Next, go to the Properties panel and click on the material icon. Create a new material with Surface>Mix Shader. Now, once you are in the Node panel, follow the material structure in the attached image. The basic structure was achieved using a Diffuse and Specular texture, mixed with different nodes to gain better control over the material output.
 

Step 15 – Render and lighting setup


Create skin shaders in Blender and ZBrush

For the lighting we used an HDR image of an outdoor scene. This image can be loaded from the Properties panel>World. Use Surface>Background and in Color use Environment Texture. We also added a single plane in front of the model where we assigned an emissive material (Strength=3) to enhance the lighting of the final scene. We used the default render settings.