Two-sided Materials

Use a two-sided Material to create the leaves of a bush or a depth effect on your mesh. Begin by selecting a base color and add onto it with more Material nodes.

1. Create a new Material in your project and double-click the Material thumbnail to open the Material Editor.

2. Select the Main Material node and check the Two Sided option in the Details panel.

   

3. Add the following nodes:

   1. 2 X Constant 3Vector expression node

   2. TwoSidedSign node

   3. Saturate node

   4. Interpolate node

4. Select the first Constant 3Vector expression node and add a color, then drag off the node and plug it into the A input on the Lerp node.

5. Select the second Constant 3Vector expression node and add a color, then drag off the node and plug it into the B input on the Lerp node.

6. Drag off the TwoSidedSign node and plug it into the Saturate node.

7. Drag off the Saturate node and plug it into the Alpha input on the Lerp node.

8. Drag off the Interpolate node and plug it into the Material root node.

   

9. Change the shape in the preview window to a flat square.

   

The configuration above treats the front and back of the mesh differently, it flips the normals so they always face the camera. If you wanted to create the illusion of depth:

1. Select the Main Material Node and change the Blend Mode option in the Details panel to Masked. This allows you to use additional input options on the Main Material Node, like Opacity Mask, which you will need to create the depth effect.

   

2. Delete one of the Constant 3Vector expression nodes and the Lerp node.

3. Add a Multiply node between the TwoSidedSign node and the Saturate node.

4. Select the Multiply node and change the B input value to -1.0.

   

5. Drag off the Saturate node and plug it into the Opacity Mask input on the Main Material Node.

   

6. Click Apply. The sphere in the preview window now has a shadow across the top.

   

7. Apply the new Material to a cube mesh. Notice how the cube looks like an empty box.

The configuration above creates a Material that only renders the inside of a solid object, causing the mesh to appear hollow from all angles. This is an interesting Material that could be used in a project to create a hall of mirrors style effect when applied.