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3. Fortnite
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4. [Fortnite Documentation](/documentation/en-us/fortnite/fortnite-documentation "Fortnite Documentation")
5. [Materials](/documentation/en-us/fortnite/materials-in-unreal-editor-for-fortnite "Materials")
6. Two-sided Materials
Two-sided Materials
===================
Learn how to create a two-sided material to create a hollow effect on your mesh.
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.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/a51232d9-d103-4286-9301-3cc6a3532e45?resizing_type=fit)
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.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/d51ff7d2-dda7-4f48-8f45-1839b660f95e?resizing_type=fit)
9. Change the shape in the preview window to a flat square.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/9918f58b-126d-4c4d-9d2c-cacbae2c6504?resizing_type=fit)
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.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/b543e67a-35b7-4a2a-940d-b98a6c483821?resizing_type=fit)
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**.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/2693549e-0ba7-41f5-9a57-7f1506ce6b68?resizing_type=fit)
5. Drag off the **Saturate** node and plug it into the **Opacity Mask input** on the **Main Material Node**.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/73439b6e-dfd3-4474-8be6-a41f4f8b3a35?resizing_type=fit)
6. Click **Apply**. The sphere in the preview window now has a shadow across the top.
[](https://uefn-docs.yuzulabs.dev/community/api/documentation/image/47eb5d34-4624-4b46-bc33-eb1efa2f95a6?resizing_type=fit)
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.
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