Troubleshoot retopology operations

This table lists mesh errors that can prevent a successful retopology operation. Mudbox automatically checks for these problems during retopology. In some cases, you can click Ignore and Continue to try the operation anyway; however, it's important to note that the retopo operation may fail, produce an unusable result, or force Mudbox to quit.

	Problem/Error Message	Possible Solution
	Non-manifold (T-shape) At least one edge in this mesh is shared by more than two faces. This must be corrected before the mesh can be used in Mudbox.	Retopology is very likely to fail if this error occurs. To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix. Select faces Patch holes in a mesh
	Non-manifold (vertex splice) At least one vertex in this mesh is shared by faces that are not a part of the same fan. This must be corrected before the mesh can be used in Mudbox.	Retopology is very likely to fail if this error occurs. To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix. Select faces Patch holes in a mesh
	Two-sided faces There is at least one face in this mesh whose boundary is made up of only two edges. Using this mesh in Mudbox will cause errors when sculpting and painting.	Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces. For better results, clean up the mesh before retopology by deleting the two-sided faces and patching the holes. Select faces Patch holes in a mesh Export the mesh to fix in Maya if necessary.
	Boundary Vertex has Too Many Edges A vertex is shared by more than two boundary edges. This must be corrected before the mesh can be used in Mudbox.	Retopology is very likely to fail if this error occurs. To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix. Select faces Patch holes in a mesh
	Interior Vertex has Valence Two A vertex on the interior of the mesh has exactly two edges connecting it. This mesh cannot be subdivided, and will cause problems when sculpting.	The retopology operation can proceed when this error occurs, but since the mesh can't be subdivided, the resulting mesh can be faceted. For better results, select and delete the corresponding faces, then patch the hole. Export to Maya if the problem is difficult to fix. Select faces Patch holes in a mesh
	Degenerated Face This mesh has faces where corners either lie on the same line or location in space.	This issue can occur in tightly detailed areas like the inner corners of the eye. Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces. For better results, try smoothing the area to make the problem faces slightly larger before retopology. (Select the Smooth tool from the Sculpt Tools tray, or press Shift to activate smoothing on another sculpt brush.
	Zero-length edges At least one edge in this mesh is zero-length. If painted, this mesh will show visible artifacts. This can be corrected by subdividing the mesh once with Smooth Positions turned on.	Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces. You can turn Smooth Positions on in the Subdivision Options ( Mesh > Add New Subdivision Level Options), then press Shift + D to subdivide the mesh. Smoothing out the area to make the problem faces slightly larger can also help.

Problem/Error Message

Possible Solution

Non-manifold (T-shape)

At least one edge in this mesh is shared by more than two faces.

This must be corrected before the mesh can be used in Mudbox.

Retopology is very likely to fail if this error occurs.

To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix.

Non-manifold (vertex splice)

At least one vertex in this mesh is shared by faces that are not a part of the same fan.

This must be corrected before the mesh can be used in Mudbox.

Retopology is very likely to fail if this error occurs.

To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix.

Two-sided faces

There is at least one face in this mesh whose boundary is made up of only two edges. Using this mesh in Mudbox will cause errors when sculpting and painting.

Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces.

For better results, clean up the mesh before retopology by deleting the two-sided faces and patching the holes.

Export the mesh to fix in Maya if necessary.

Boundary Vertex has Too Many Edges

A vertex is shared by more than two boundary edges. This must be corrected before the mesh can be used in Mudbox.

Retopology is very likely to fail if this error occurs.

To fix the issue, select and delete the offending faces, then patch the hole. Export to Maya if the problem is difficult to fix.

Interior Vertex has Valence Two

A vertex on the interior of the mesh has exactly two edges connecting it. This mesh cannot be subdivided, and will cause problems when sculpting.

The retopology operation can proceed when this error occurs, but since the mesh can't be subdivided, the resulting mesh can be faceted.

For better results, select and delete the corresponding faces, then patch the hole. Export to Maya if the problem is difficult to fix.

Degenerated Face

This mesh has faces where corners either lie on the same line or location in space.

This issue can occur in tightly detailed areas like the inner corners of the eye. Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces.

For better results, try smoothing the area to make the problem faces slightly larger before retopology.

(Select the Smooth tool from the Sculpt Tools tray, or press Shift to activate smoothing on another sculpt brush.

Zero-length edges

At least one edge in this mesh is zero-length. If painted, this mesh will show visible artifacts. This can be corrected by subdividing the mesh once with Smooth Positions turned on.

Retopology can still succeed when this error occurs, but the resulting mesh can have holes or artifacts around the problem faces.

You can turn Smooth Positions on in the Subdivision Options ( Mesh > Add New Subdivision Level Options), then press Shift + D to subdivide the mesh.

Smoothing out the area to make the problem faces slightly larger can also help.

Troubleshoot retopology operations

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