I am trying to create a terrain- 3d view with multiple dem files but seem to only be able to open one per view. How do you add more dem's to the view?

You can combine surfaces into one single surface by copy/paste. Then the terrain of the combined surface will be able to view them all as one.

cuda shuda wuda

sorry - new to this program but have been trying several things - where do you copy / paste.

Ensure that in Tools/Options "Confirm expanding images or surfaces when pasting" is checked. Also ensure your projections are assigned correctly first - do they line up correctly when all viewed in one Map?

Choose one of your sufaces to be the "parent".

Open another surface, select all pixels and click Copy on the edit toolbar or press Ctrl-C (or just right-click the component in the project pane and choose Copy).

Go to the parent, and click Paste on the edit toolbar.

See this page: http://www.manifold.net/doc/copy_and_paste_in_images.htm

It works the same for images and surfaces.

cuda shuda wuda

1. Open a source surface / ctrl+a / ctrl+c or right click and copy in the project manager

2. Open a destination surface / ctrl+v or edit->paste append

3. Click ok, when asked whether to expand the surface

4. Read the manual carefully :-)