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Removing Objects from DTM

In this description, the term DTM actually refers to a DTM set, meaning an Existing DTM as well as (potentially) a Proposed DTM and a Cut and Fill DTM.

After a DTM has been created, it keeps track of which objects serve as data. You can add selected points and/or polys to the DTM by choosing Object > Add to DTM.

This act of adding to a DTM doesn't change what kind of DTMs are created in the DTM set. If the DTM set only consists of an Existing DTM, and you add, for instance, a poly whose purpose is a road, then you still have to select the DTM set and cause the Proposed DTM to be created. This cannot be done in the Standard version of SimuTerra.

If you select one or more objects, then choose Object > Remove from DTM, the following happens for each of the selected objects:

• If it is a point or poly being used as data by any DTM, then that DTM is instructed to no longer used that object as data.

Then any affected DTM is recalculated.

This command has no direct effect on selected DTMs or entels, or on points or polys which are not serving as data for a DTM.

You should try to avoid removing so much data from a DTM that it no longer has enough data from which to be calculated. A DTM needs at least three non-collinear points (or poly vertices) (not modifiers such as roads) in order to sustain itself.

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