View Full Version : Measuring distance on terrain / landscape

06-02-2007, 09:50 PM
I'am working on a realtime visualization project. I have this landscape / terrain mesh created in 3ds max and I want to implement a measuring feature in the application. That is, when the user klick point A and point B the application will calculate the distance between the two choosen points. The actual distances that the user might want to measure range from 1 - 1000 m, with an accuracy of about 1 m.

I have tought about building a database with [vertex pair, distance], and then do a lookup in this when the user access the feature. But I'am afraid that this database will be too big. (If 3ds max don't have a automatic tool to build such a database then it's certainly out of the question since building so many value pairs by hand is unpractical.) So I wondered if someone has some general thoughts about how to implement a feature like this? Maybe there is a way to convert screen distance into realworld distance? Or maybe there is another "trick of the trade" that I am not aware of?

PS! If this is the wrong forum for this kind of question, please let me know.


Ian Jones
06-03-2007, 12:21 AM
As the crow flies? or along the course of the terrain up and down hills?

Either way you'll have to do some maths. Geometry and Trig.

Ian Jones
06-03-2007, 12:23 AM
I forgot to ask if you were using an existing 3d engine? because it is likely this kind of functionality is built in or at least documented somewhere.

06-03-2007, 07:30 AM
Up and down the hills is the best, but i can settle with the crow version :) I'am working with the Lingo scripting language, so I do not know if there is any prebuilt tools for this. But i will surely read my docs and books once more too se if it exists :)

It is something like the "Tape Helper" in 3ds max I am looking for.

Ian Jones
06-03-2007, 12:09 PM
ahh yes, lingo... :)

Regardless of the language these are pretty much standard trigonometry problems. Check out trigonomtery tutes on the net. I'm pretty bad at maths, so I always use these as a nudge in the right direction.

06-24-2007, 12:50 PM
A series of ray-mesh intersections spanning the horizontal distance between the two points of interest whilst summing the distances between the intersection points. That would be a quick and dirty solution.

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