[therion-users] Re: New version

Wookey wookey at aleph1.co.uk
Wed Nov 6 15:41:38 CET 2002

On Wed 06 Nov, Stacho Mudrak wrote:
> Of course, you're right ;-) The build process is now done a very dirty way
> and I'm very interested in, to make it GNU compatible (automake etc...), but
> we've a lot of other things on TODO list, that are too hot...

OK - that's fine. If I'm going to package it for Debian then that will be a
good excuse to work on the build system a little. You carry on with the
good work on the application itself and I will try to improve the build
environment. In consultation, of course - until I get a better feel for how
it all fits together I might do unhelpful things if I don't check :-)

> If you're interested in, I can send you the map of our real (2 km) test cave
> (cca500kB in PDF, 40kB in therion format - if you're able to run therion -
> it would be a very nice test), that you will see, how the map of real cave
> processed by therion looks like.

Please do - That would be brilliant. A real example is always very useful
indeed in understanding things.

> We can not put it on the web, as a motivation for other people, because it's
> very "sensitive" cave ...., when we're able to put into maps all we need,
> we will probably be more editing maps than programming.

Well I was intending to try it out on a short map as soon as I can. I'll
make sure it is one we can distribute as an example.
> Then 2D output should be more or less finished (ha - it seems I'm still
> optimistic). But we urgently need some 3D passage model. It'll be a part of
> xtherion, because I've found one very nice parser of OpenGL into Tcl/Tk.

You know that survex-aven now has an openGL version in alpha form (ie it
works but isn't generally available) which doea nice 3D models based on
LRUD. the missing part is reading in the LRUD info (it makes them up at the
moment according to leg-length, which is remarkably effective as a

I thought therion was for drawing 2D maps and tools like aven were for 3D
visualisation. Perhaps I am wrong, but it is good not to do the same work
twice if it is not necessary...

> Our goal is to minimize entering up-down-left-right data, but using map
> plan, extended profile and given sections (all parts of 2D input) generate a
> 3D passage wall model. I'm very keen on testing such an algorithms, because
> I've never seen something like this and I believe, it would save our time
> and improve the 3D model.

That is certainly a very good thing. In fact I have a need for somethng
similar. I have just been given all the Mulu data for the last 20 years.
Unfortunately most of the 1980s original centreline data has been lost - we
only have the drawn-up surveys. Now that computer 3D visualisation is so
important in caving it would be _really_ useful if there was some software
that could let you regenerate the (approximate) centreline data from the
plan and elevation. Doing this is quite similar to using the 2D drawings to
add LRUD info. Can you make it do both of these things? The difference is
the need to cross-reference the plan and elevation points, rather than
reference the plan or elevation to the centreline independently.

Does that make sense? Does it seem do-able?

> Of course in parallel, we're planing to write some therion cookbook. README
> file now serves more like a reference guide, because sometimes I forget, how
> I've programmed something.

I should be able to help with docs. I did (most of) the original survex
manual when it badly needed one. Time is always a problem of course but
I'll see what I can do.

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