Line of intersection between DTMs

You can use this function to find the line of contact where two DTMs intersect. The line follows the exact path of intersection between the two DTMs, wherever DTM triangles intersect. To use this function, you must have the DTMs of interest open in Graphics, and the DTMs must be created on the same plane.

You can use the string file produced by this function for many purposes. For example:

to delineate exactly between cut and fill material for volumes
to find where a DTM of a fault plane intersects a surface
to find where a DTM of a pit design intersects the natural surface

To run this function: Choose Surfaces > Clip or intersect DTMs > Line of intersection between 2 DTMs, or...

In the Function Chooser, type GRAPHICS INTERSECT DTMS, and press ENTER.

Fields on the Intersect DTMs for line of contact form

Field	Description
First DTM layer	The layer that contains the first DTM. To select a DTM, it must be open in Graphics.
Object ID	The object number of the first DTM.
Trisolation ID	The trisolation number of the first DTM.
Second DTM layer	The layer that contains the second DTM. To select a DTM, it must be open in Graphics.
Object ID	The object number of the second DTM.
Trisolation ID	The trisolation number of the second DTM.
Define result file
Output layer	The name and location of the layer to store the results of the intersection. Note: This layer is not saved. If you want to keep the data, you must save the layer.
String Number	The string number in which to store the contact line segments.

Output

The DTMs are intersected, and the string file of the lines of contact is created and displayed in a new layer.

Tip: If the line of intersection is not closed, you can manually close the segments using the Consolidate Segment function.

Troubleshooting

Message	Description
`Cannot intersect a DTM by itself`	You have selected the same DTM to be intersected in both the first DTM and second DTM field, this is not allowed.
`There are less than two valid DTMs loaded into Graphics.` `You need at least two DTMs loaded to perform this function.`	There must be at least two DTMs in separate layers in GRAPHICS to perform this function.
`No intersection found between the DTMs` `Cannot join segment XXX of string YYY`	The DTMs do not intersect, you must choose DTMs with areas of intersection to perform this function.
`The selected DTMs were not created on the same plane.`	The DTMs used must be created on the same plane. Choose different DTMs, recreate the DTMs on the same plane, or transform the data in one of the DTMs to match the plane of the other.