Drawing contours

[johnharley]

Question: What is the best type of polyline to use for drawing contours? For instance, if you are tracing them from a scanned document. I would also like to be able to export them later to AutoCAD and have them show up as fully editable p-lines.

[Guest]

If you want to use polylines in VW for creating a DTM, you will need to convert them to 3d polygons and assign a z height to them once they are drawn.

[Kevin]

Katie;Exactly what is a polyline? I see a line tool. I see a polygon tool.

In your example, am I correct in this understanding:

1. Scan document.2. Import document.3. In a separate layer, trace the contours with "polylines", (whatever those are).4. Select all and choose the "Convert to 3d Poly" command.5. One, by one, select each 3d poly and in the Info Palette set the "Z" height.

Thanks for your help.

[Guest]

A polyline is a line that can be closed and given a fill, or it can be left open with or without a fill. It's generally a line, but allows you to incorporate vertex points giving you greater flexibility. It can be drawn wtih 4 mode types, straight and 3 types of curves.

The polygon tool only allows you to draw straight lines - no curves.

However, you can convert objects to a polygon which can then be extruded. Or you can convert them to 3d polygons, which can be manipulated along the z axis as far as height.

If you are scanning an image, yes the best way to go about it would be to do as you said. Scan imageimport image to it's own layerTrace over the contour lines in a new layer making that your exisitng data layer with the polyline tool.

Then you can convert them to 3d polygons and specify the z height for each one.

Then you can make your site model based on the data provided.

[Andrew G. Buck]

"convert them (2D polylines) to 3d polygons"

Can you point me to the tool to do this?

Thanks,

andy