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convert heightmap to mosiac of low rez obj files?

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convert heightmap to mosiac of low rez obj files?

Postby mbaucco » Sat Apr 09, 2011 4:32 pm

Hello,

I am trying out L3DT in the hopes that it will work for a project. I am trying to create a landscape in the Blender Game Engine that consists of a grid of separate terrain objects that fit together without seams. Although I can do this in L3DT pro, I can not figure out how to get the program to produce "chunks" that are around 1k polys. There will be 9 chunks loaded at any one time, and I do not need more detail than that for my terrains, as each chunk will represent a 256 meter square. I tried decimating the tiles in Blender after importing but this of course ruins the edges.

Since I am going to have hundreds of these tiles I want to automate this process as much as possible. I am really hoping I can do this with L3DT, because so far I like the program very much!

Thanks,
Matt
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Re: convert heightmap to mosiac of low rez obj files?

Postby Aaron » Mon Apr 11, 2011 12:59 pm

Hi Matt,

I apologise for my slow reply. L3DT doesn't yet have the ability to decimate tiled maps. I intend to this feature in the next major release, but I can't offer an ETA at this time. I am presently bogged down in updating the documentation, but once that is done the tiled mesh decimator should be the next cab off the rank.

Thanks for the request/reminder.

Best regards,
Aaron.
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Re: convert heightmap to mosiac of low rez obj files?

Postby David Walters » Thu Jun 09, 2011 9:32 am

Bumping this slightly older topic given the recent progress in build 22.

I too am interested in this decimation feature as an alternative to working with plain height data. It would feed into my tool chain quite nicely I think. It would certainly make it easier to hand edit the terrain in Silo et al. as an intermediary step before rendering.

So, there is currently a 'max error' parameter in the latest mesh exporter - would an alternate option for a 'per-tile triangle limit' be easy to add? With the acknowledgement (and hope) that it will still favour seamless edges over precisely hitting this limit - a little overspill would be perfectly fine.

I'm not too familiar with the decimation capabilities, but hope this is an easy thing to add now?

edit: Hmm, did a quick test and it looks like the majority of the triangles are used in making the seamless edges. So this request probably won't be much use unless the tile size is very large. Perhaps there could be an option to decrease the detail along the tile edges, with maximum quality reserved for just the corners?
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Re: convert heightmap to mosiac of low rez obj files?

Postby Aaron » Thu Jun 09, 2011 12:13 pm

Hi David,

It would be possible, in theory, to give the decimator a triangle limit. This would require the decimator to sort triangles in order of variance before splitting, which is feasible but will be a bit slower, and certainly would involve a quite a bit of re-engineering of the decimator. Another approach would be to have the decimator iterate the max error threshold automatically until the triangle count is just below the specified limit. This is less work on my part, but it could be a staggeringly slow algorithm (10 times as long, for instance).

Perhaps there could be an option to decrease the detail along the tile edges, with maximum quality reserved for just the corners?


I'm not sure that would be feasible with the the current decimator design. In the fullness of time I may be able to modify the decimator to use triangles that are optimised consistently across tile borders (instead of using unoptimised triangles), as this approach would spend no additional triangles in enforcing seamless edges. However, that would still require quite an investment in time and thinkering, so it's not going to happen in the near future given the other items on the current dev plan.

Anyway, thanks again for the suggestions. I'll pop both of these requests on the to-do list for 'unscheduled features'.

Best regards,
Aaron.
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