To create a new DTM, activate a layer which has at least three 3D loci, or at least one 3D polygon with at least three vertices.
Could not or did not create the DTM.
The active layer must be one which is associated with an existing DTM.
You must select exactly two DTMs.
Neither DTM totally encloses the other.
One of the items is invalid.
You must choose two different DTMs in the popup menus.
The "To" DTM must be totally enclosed by, or have the same border as, the "From" DTM.
The DTM name and the output layer names must not be left blank.
You must enter a unique name for this DTM and each of its output layers; the name that you entered is already in use.
The major multiple must be an integer greater than zero.
The contour interval must be greater than zero.
The name of the DTM and the names of the output layers must be different from each other.
The name may not have more than 20 characters.
Both the "from" and the "to" DTMs must be normal DTMs; neither is allowed to be a cut & fill DTM.
One or both of the DTMs you selected could not be found.
Both of the DTMs you selected must be resident; you must calculate whichever one(s) is(are) non-resident with the "Always recalculate" option turned off.
