Sprite Editor: Custom Outline

Use the Sprite Editor’s Custom Outline option to edit the shape of the Mesh that Unity renders the Sprite texture on. The Custom Outline editor allows you to use control points to create and define the shape of the Sprite’s Mesh outline.

By default, Unity renders each Sprite on a rectangle Mesh. This Mesh might include transparent areas outside the Texture’s border, and rendering these transparent areas can negatively affect performance. When you use the Custom Outline editor to define a Mesh outline that matches the outline of the Sprite Texture, you reduce the size of the transparent areas, which improves performance.

To access the Custom Outline editor, select a Sprite and then in the Sprite’s Inspector window, select the Sprite Editor button. In the Sprite Editor window, open the upper-left drop-down menu and select Custom Online to open the Custom Outline editor.

The Custom Outline editor

Custom Outline editor properties

Using the Custom Outline editor

The Custom Outline editor allows you to to create or generate the Mesh of the Sprite. There are two ways to create a custom outline: have Unity automatically generate the shape, or manually creating and editing it in the editor window.

Generating the outline

To have Unity automatically generate an outline that follows the shape of the original Sprite texture, and that also takes into account transparent areas in the texture, click the Generate button. However, you can adjust how tightly the generated outline follows the Sprite texture by adjusting the Outline Tolerance slider.

Adjust the Outline Tolerance slider to refine the outline of the Mesh that Unity generates. Increasing the value increases how closely the outline follows the shape of the Sprite texture. Leaving the slider at 0 generates a Mesh that more loosely follows the Sprite texture.

Editing the custom outline

You can create your own custom shape and edit it in two ways. The first way is by automatically generating an outline, and then moving the control points of the generated outline to further refine its shape. Alternatively click and drag over any space in the Custom Outline editor window to create a rectangular outline with four control points and begin refining the outline by moving the control points or adding and removing them.

Click and drag over the Sprite texture in the editor window to create rectangle outlines with four control points. Repeat this step to create multiple Mesh outlines within the Sprite. Unity only renders the areas enclosed within the Mesh outlines.

Moving control points

To adjust the shape of the Mesh outline, click and drag its control points. When you hover over a control point, it turns blue to indicate that you can select it. Click and drag the control point to different positions to adjust the shape of the Mesh outline. You can select multiple control points at once by clicking and dragging the cursor over an area to select all control points within that area. You can then re-position or remove all selected control points altogether.

Adding/Removing control points

To add a control point, place the cursor over the edge of the outline. A preview of the control point appears along the outline’s edge. Click to add a new control point at that location. To remove a control point, select it and press the Del/Command+Del keys.

Moving edges

To move a section between two control points, hold the Control/Ctrl key to select the edges of the outline instead of its control points. To change the shape of the outline, click and drag the highlighted edge to move them into new positions.

• Copy and Paste editor window functions added in 2020.1 NewIn20201
• 2018–10–19 Page amended
• Edit Outline renamed to Custom Outline in Unity version 2017.3.