Having to download, convert and manage DEMs can be a pain, so here's an attempt to do 3D without DEMs -- only with the elevation data available in the tracklogs themselves:
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And here is what it looks like using the DEM:
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This is the backside of Mt. Lemmon and it works fairly well since I have trails down the some of the ridges and in the CDO valley. Â It won't predict peaks or valleys that it doesn't have data on, but it can be kind of cool if you've got a fair amount of data in an area.
It'll be in the next beta (hopefully soon) just as a different interpolation method in 3d options.