Quick Tip: Create Seamless Lizard Skin in Modo

In our latest Modo quick tip, you'll learn how to create seamless lizard skin in Modo from 3D geometry. Tomasz Lechociński will walk you through the process of modeling a tileable scale pattern, and how to bake it down into a set of Normal and Ambient Occlusion maps. You'll then learn how these can be used, along with Photoshop, to build a great looking Modo shader for all your reptilian needs.

1. Modeling the Scales in Modo & Baking them to Bitmaps

Step 1

You'll model the scales in Modo and bake them to create Normal and Ambient Occlusion maps.

Change your 3D view to Front
Create a new Empty Mesh item in the Item List.
Change its name to "baker".
Run the Box tool and type the values as shown in the screen grab. Position: 0 on every axes, Size X: 5cm, Y: 5cm, Z: 0cm.
In the Vertex Maps List, create a New Map and call it "Baker"

Note: The name of the UV map for this mesh must be unique in this Modo file. This means that no other active mesh can have a UV map with the same name. Otherwise Modo will generate errors when baking.

Step 2

Building the model for the scales.

Create a new Empty Mesh item in the Item List.
Change its name to "scales 2D".
Run the Vertex Tool and in Vertex Selection mode, add 8 points in the order shown below.
When you're finished, press P on the keyboard to create a polygon from the drawn points.

Make sure that points 1, 3, 5 and 7 are aligned with the baker mesh below, as shown in the screen grab.

Step 3

Now we'll add more scales.

In Polygon Selection mode, select the polygon that you created and press Control-C to copy it.
In the Tool Properties, turn On snapping (1)
Change its values to the ones shown in the screen grab.
Activate the Move Tool (W) and move the geometry to the left corner of the baker mesh. From point (2) to point (3). A Yellow dot will show up when the geometry will snap to the point on the corner of the baker mesh.
Press Control-V to paste the polygon in its original position.
Turn Off Snapping. You have to do this, otherwise you won`t be able to draw points with the Vertex Tool in the next step.

Step 4

Fill the space between the polygons with small scales. Use the Vertex Tool like we did in Step 2.

Step 5

Copy the created geometry to the bottom side of the baker mesh.

Select all the polygons that you created.
Press Control-C to copy them.
Turn On Snapping with the settings from Step 3.
Activate the Move Tool (W) and move the geometry (1) to the bottom (2) of the baker mesh.
When the Move Tool is still active, you can press Control-V to paste the copied polygons in their original position.
Turn Off Snapping. You have to do this otherwise you won`t be able to draw points with Vertex Tool in the next step.

Step 6

Now fill the right side with sets of scales. Use the Vertex Tool again, like we did in Steps 2 and 4.

Step 7

Now move the selected geometry to the left side of the baker mesh.

Select the polygons and copy them, press Control-C to do that.
Turn On Snapping, and again use the settings from Step 3.
Activate the Transform Tool (Y).
Click on the point (1) and see how the transformation gizmo snaps to that vertex.
Move the geometry using the red arrow of the Transform Tool to the left side of the baker mesh (2).
Press Control-V to paste the geometry in its original position.
Turn Off Snapping.

Step 8

Go to Geometry > Mesh Cleanup to get rid of the overlapping geometry on the corners.

Step 9

Fill the inside of the rectangle with both small and large scales. Again use the Vertex Tool like in Steps 2 and 4.

Step 10

Now it is time to add volume to the scales

Duplicate the scales 2D mesh.
Change its name to "Scales 3D".
With the Scales 3D mesh selected, in Polygon mode, press B to activate the Bevel tool.
Extrude it with the following values: Shift: 500 um, and Inset: 300 um.

Step 11

Change the display of the Scales 3D mesh to Subdivision mode. To do that press the TAB key.

Step 12

Now to add another piece of geometry to the Scales 3D mesh.

Activate the Box tool and set its Size on X and Y to 5 cm, and its Position to 0, 0, 0.
Click Apply to add the geometry.

Step 13

Now create a new material for the baker mesh.

Select the baker mesh.
Press M to create a new material and name it "baker".
Now add a new bitmap to the Shader Tree using Add Layer > Image Map > (New Image).
Name it "Lizard skin normal" and choose JPG as the file format (1).
Set its Resolution to 1024x1024.
In the Shader Tree, Right Click on it in the Effect Column, and change its effect by going to Effect > Surface Shading > Normal.
In the Texture Locator sub tab (2), set its UV Map to Baker
Make sure that the baker mesh is selected in the Item List.
Now Right Click on the image in The Shader Tree, and choose Bake from Object to Texture.
Set its Bake Texture From Object Distance to 1cm when prompted.

Step 14

Now that the map is ready, you can save it to disk as "Lizard skin normal.JPG", using the Save Image button (1).

Step 15

It's time to change the frame size of this scene.

In the Shader Tree, select the Render Item (1).
In the Frame sub-tab, change the Frame Width and Height to: 1024

Step 16

Add another Output layer to the shader tree. This time it will be Ambient Occlusion, which simulates the effect of self shadowing on all the geometry in the scene. It will help to attenuate the silhouette of the scales.

In the Shader Tree, select Add Layer > Special > Render Output.
Change its Effect to Ambient Occlusion (1).
In its Properties panel, change the Occlusion Rays to 512 and the Occlusion Range to 2.12 cm.
Make sure that the baker mesh is selected in the Item List (2).
Make sure that the Baker vertex map is selected in the Vertex Map List (3).
Go to the top menu and choose Render > Bake From Object to Render Outputs.
Set its Bake Outputs From Object Distance to 1cm when prompted.

Step 17

Save the render to disk.

From the Output (1) drop-down menu, choose Ambient Occlusion.
Then press Save Image (2), to save the currently displayed render output do disk.
Save it as "Lizard skin AO.jpg"

Save the file for later use. You'll be able to create many different types of scales this way.