Re: [Update REQ 6062]: loading lines/points

[daemon]

> I am looking for assistance with the loading of these lines into Geomview.
> I have come to the conclusion that I probably want to create a .vect file 
> specifying the vertices of all the lines.

Yes, that's probably best.  Would an example VECT file help?
Here's a simple one, containing two "polylines" (two polygonal curves,
one with three points, the other with four points, with no colors specified):

VECT
2 7 0		# We have two polylines, with a total of 7 points, no colors

3 4		# First polyline has 3 points, second polyline has 4 points

0 0		# First polyline has no colors, so does the second

	# Now we specify all the X Y Z vertex positions for all the polylines,
	# which appear in the same order as mentioned in the header,
	# i.e. first the three vertices for the first polyline, then the
	# four vertices for the second.  There's nothing to mark which vertices
	# go with which polyline.  We add an extra blank line for clarity,
	# but the software doesn't care.

0 1 0
0 1.5 1
1 1.5 1

-.5 1 1
-.5 1.5 1
.5 .5 .5
1  1 0

	# Now, if we had specified any colors, they'd appear here.
	# Since there aren't any, the lines will appear black by default,
	# but this can be changed via geomview's "Edge color" controls
	# on the appearance panel.

In general, if you have a bunch of polygonal curves, you just write out
all their vertex positions in sequence, preceded by a header like:

VECT
<npolylines>  <totalvertices>  <totalcolors>

<nvertices-for-polyline-1> <nvertices-for-polyline-2> ... <nverts-for-polyline-n>

<colors-for-polyline-1> <colors-for-polyline-2> ... <nverts-for-polyline-n>

Line breaks aren't significant -- they're separators just as blanks are --
so you could write the above example's header just as well as

VECT 2 7 0 3 4 0 0

or equivalently as

VECT
2 7 0

3
4

0
0


For a more elaborate example which does use colors, see the VECT section in
the file "doc/oogltour".


  Stuart Levy, Geometry Center