Thanks! And yeah, osm2world is almost perfect for what I need, and I’m a big fan of opensource - all the components I’ve used are opensource as is the code I’ve written
Well, 0.5m might have been a bit of an underestimate, as I think the error varies. Infact, my guess is that the error linearly increases as you move away from some point which maybe the .obj is centered on.
I’ve got a couple of examples, the first is here . This is the standard obj I’ve been using, and covers about 1.5km by 1.5km. This far zoomed out, it doesn’t look so bad, but in the earlier screenshot (http://people.bath.ac.uk/vb216/accuracy.PNG) thats pretty big, maybe 2 road widths to give it context.
Now, I used the latest osm2world build, as from emails with Tobias there was a new projection approach put in. And this time, I get this: - sorry the colours aren’t so clear here, the route is shown in red. The interesting thing here, is that the error looks consistent on the east of the route. Infact, in the 3D view, I added some controls to shift the xy of the obj, and to stretch/shrink on the xy axis too. If I shrink by about 0.93 on the east-west axis, it looks pretty good. But, when I tried this in earlier osm2world, I still didn’t get a great fit.
The other thing worth mentioning, is coordinate system. So, use a local xyz with meter units. From the .obj generated from osm2world, I run it through the openscenegraph osgconv as that seems to make the model appear better in the 3D engine, and then load the .obj in the renderer. I’ve got xy offset values where I’ve put a vehicle at a known location, and aligned the .obj to that position by shifting those offsets. So that’s why the bottom south-west of the route seems to align so well.
So I think, I’m pretty much using UTM, just with the positions all zero’d to a local position, to keep all my numbers a bit more manageable. I did wonder if it was some lat/lon zone type thing, but then I wouldn’t have expected to see it having that big an impact over a small 1.5k area… but, I’ve never really looked into that conversion stuff in huge depth.
If there’s any code I can show that would help then let me know, but I’m not really handling any projection conversions as I thought everything was shifted to UTM.
Oh yes, one other thing I checked, if I go to the lat-lon in the osm2world GUI, for the converted UTM coords of those waypoint positions shown in the url links, it appears in the right place.