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Quick Tip: Create Seamless Lizard Skin in Modo

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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.

Modo_Lizard_Skin_1_1

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.

Modo_Lizard_Skin_1_2

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.
Modo_Lizard_Skin_1_3

Step 4

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

Modo_Lizard_Skin_1_4

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.
Modo_Lizard_Skin_1_5

Step 6

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

Modo_Lizard_Skin_1_6

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.
Modo_Lizard_Skin_1_7

Step 8

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

Modo_Lizard_Skin_1_8

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.

Modo_Lizard_Skin_1_9

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.
Modo_Lizard_Skin_1_10

Step 11

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

Modo_Lizard_Skin_1_11

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.
Modo_Lizard_Skin_1_12

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.
Modo_Lizard_Skin_1_13

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).

Modo_Lizard_Skin_1_14

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
Modo_Lizard_Skin_1_15

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.
Modo_Lizard_Skin_1_16

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.

Modo_Lizard_Skin_1_17

2. Create a Simple Reptile Pattern in Photoshop

Step 1

To add some color to the lizard skin material, you'll need to create a reptile pattern.

  • In Photoshop, create a new 1024x1024 pixel, Gray Scale document.
  • Fill the Background layer with a pure Black color.
  • Activate the Pen tool and make sure its mode is set to Shape.
  • Draw an organic pattern on the canvas, and make sure that this shape is filled with a pure White color.
Modo_Lizard_Skin_2_1

Step 2

Add a Layer Effect to the shape you have created, and set the Inner Shadow parameters as shown.

Modo_Lizard_Skin_2_2

Step 3

Now save your image to disk as "Lizard skin pattern.png"

Modo_Lizard_Skin_2_3

3. Creating the Lizard Skin Material in Modo

Step 1

Download the default-preset scene from the Luxology forums: Luxology Forums or search the Luxology forums for PresetScene-Yazan.lxo, to get the latest version (there are also videos available that explain its usage.)

  • In the Shader Tree, open the 9ball group.
  • Select the material inside it and change its name to: "Lizard skin base".
  • Change its properties in the Material Ref sub-tab, as shown in the image below.
  • Leave the Material Trans sub-tab without any changes.
  • Press Control-G to add another group and name it: "Seamless lizard skin".
Modo_Lizard_Skin_3_1

Step 2

Now change the surface shading to give the impression that the surface is more complex then it is in reality.

  • In the Shader Tree, go to Add Layer > Image Map > Load Image.
  • Locate the Lizard skin Normal.JPG image on disk and pick it (1).
  • Right Click on it and change its Effect to Surface Shading > Normal.
  • Next, go to the Texture Locator and set its UV Map to Texture.
  • Set its Horizontal and Vertical Wrap values as shown in the image below.
Modo_Lizard_Skin_3_2

Step 3

Now we'll add another layer, but to see its effect, you need to temporally change the properties of the Preview Window.

  • In the Preview Window, locate the button labeled Effect (1) and change its effect to Shading Effects > Shader Control > Driver A. The preview window will turn black for now, but don’t worry it's all right.
  • In the Shader Tree, go to Add Layer > Image Map > Load Image (2).
  • Locate the Lizard skin Pattern.PNG on disk, and choose it.
  • Right Click on it and change its Effect to Shader Control > Driver A. (Now the image is back in the preview window).
  • Next, go to the Texture Locator and set its UV Map to Texture (3).
  • Set its Horizontal and Vertical Wrap values as shown in the image.
Modo_Lizard_Skin_3_3

Step 4

Now to restore the typical preview window view. In the Preview Window, locate the button labeled Effect (1), and change its effect to Shading Effects > Final Color Output.

  • In the Shader Tree, go to Add Layer > Processing > Gradient.
  • Change its Input Parameter to Shader Control > Driver A.
  • Press Edit Gradient and with the three Color channels selected, press the Middle Mouse Button to add 2 keys.
  • Give Key (1) a Yellow color, and Key (2) a Black color.
  • Change the Layer Blend Mode to Multiply, and set its Opacity to 70%.
Modo_Lizard_Skin_3_4

Step 5

Now add another color layer.

  • In the Shader Tree, go to Add Layer > Processing > Gradient.
  • Press Edit Gradient and with the three Color channels selected, press the Middle Mouse Button to add 2 keys.
  • Give Key (1) a Yellow color ( #d6ff63), and Key (2) a Green color ( #368c33).
  • Change the Layer Blend Mode to Multiply, and set its Opacity to 62.5%.
Modo_Lizard_Skin_3_5

Step 6

Now add another Color layer.

  • In the Shader Tree, select the last gradient layer and from the Right Click menu, choose Create Instance.
  • Change the Layer Blend Mode to Multiply, and set its Opacity to 62.5%.
  • Change its Effect to Basic Channels > Reflection Color.
Modo_Lizard_Skin_3_6

Step 7

Now add another layer, this time it will drive the reflections on the skin surface.

  • In the Shader Tree, go to Add Layer > Processing > Gradient.
  • Change its Effect to Basic Channels > Reflection Amount.
  • Press Edit Gradient, and with the Value channel selected, press the Middle Mousse Button to add 2 keys.
  • Give Key (1) the following values, Input: 0% Value: 1%. And Key (2) the values Input: 100% Value: 20%.
Modo_Lizard_Skin_3_7

Step 8

Now its time to add the final layer.

  • In the Shader Tree, go to Add Layer > Image Map > Load Image.
  • Locate "Lizard skin AO.JPG" on disk, and choose it (1).
  • Set its Blend Mode to Multiply.
  • Next, go to the Texture Locator and set its UV Map to Texture.
  • Set its Horizontal and Vertical Wrap as shown in the picture.
Modo_Lizard_Skin_3_8

Step 9

Save your now ready seamless lizard skin Preset.

  • In the Shader Tree, select the Seamless lizard skin group and from the Right Click menu, choose Save Preset With Thumbnail ...
  • Save it to disk.
  • Press F9 to render it.
Modo_Lizard_Skin_3_9

Step 10

Change the icon for the saved Preset.

  • In the Preset Browser palette, navigate to your Preset.
  • Right Click on it and choose Replace Icon with Last Render.

You now have a ready made basic skin for any type of reptile.

Modo_Lizard_Skin_3_10

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