The Cutout Editor is a tool that allows you to create your own meshes for a material without having to use an outside program. In the Cutout Editor, there are many controls that can help you achieve high-detail meshes as well as optimized meshes for game assets.
You can access this editor by clicking the “Edit” button in a particular mesh asset. If you have applied a mesh to a material (or wish to create a new mesh for a particular material), you can also use the shortcut “Edit” button in that material asset.
There are three main groups of tools found at the top of the Cutout Editor: Points, Masks, and Anchors.
The Points tools allows you to add, move, and delete vertices in the mesh. Triangulation between these points is automatic. If you are editing a mesh for a material with an opacity channel, any completely transparent triangles will be removed automatically.
Add points by clicking in empty space. You can also move existing points by clicking/dragging them.
Reset the points to the default layout (a square).
The pivot point is a special point in the mesh that is displayed as white. This point cannot be deleted, but it can be moved. Its position is used as the origin of the mesh.
Transparent triangles will be automatically removed, but your material may not have an opacity channel. Or, you may just want to have a little more control over triangles that are removed. For this, you would paint a mask. Anywhere the mask is painted will have triangles removed.
Paint a mask.
Erase parts of the painted mask.
Reset the mask to default (empty).
The Anchors group allows you to add/edit mesh anchor points for where children will grow.
Add mesh anchor points by clicking in empty space. You can also move existing points by clicking/dragging them.
Each anchor point has a white line coming from it that indicates the growth direction of anything placed there. You can drag the white dot at the end of this line to set this direction.
Delete mesh anchor points.
Reset the anchors to default (none).
This option sets the material shown in the preview, and affects the aspect ratio of the mesh created (to match the material). If you edit a new cutout mesh by clicking the “Edit” button in the material asset bar, this option will already be set to the correct value.
If you wish to have more triangles in the mesh so it will work better for fold, curl, or other deformations, you can add them using the tessellation control. It will intelligently subdivide the existing triangles.
Occasionally you will want a double-sided mesh, which can often light better on things like palm fronds. This option will duplicate the mesh and flip the new one to face the other way.
If your texture/material isn't quite aligned with the Y-axis, use this option to rotate the final mesh after creation. The new y-axis is indicated by the orange line.
Once you have created a mesh, you still need to “save” it to the mesh asset. You do this by clicking the “High,” “Med”, or “Low” buttons to store the mesh data in the corresponding mesh level. “High” is the regular place to save the mesh data, but you may want to make lower quality meshes for use with LOD or Resolution as well.