v18: low resolution in 3D view

kfroesekfroese Geotechnical EngineerPosts: 170Trusted User
I have a large 1m grid LiDAR DEM for a river valley. I was hoping to look at it in 3D to aid in determining landslide locations. However, my 3D view is significantly lower in resolution than the source data. I've attached a screen shot of both 2D and 3D. I get the same result whether the 3D view is docked or floating.

Am I doing something wrong?
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Best Answer

  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324
    Answer ✓
    Hi folks,

    When we switched from the old "shoebox" view to "infinite" view, we had to balance between UI responsiveness and immediate rendering fidelity, particularly with terrain. The terrain should start out low-res, but gradually fill-in with the higher resolution data over time; it can take a while to pull in all of the data required to render at full resolution, so we settle initially for low-res data to fill in. We realize that this is not always optimal, but it's a bit of a balancing act, and we're still looking at ways to improve both speed and rendering quality. If you're not seeing the quality improve over time, that may be an an indication of a situation we've not come across yet. In that case, you should open an issue with our support folks. I'm not sure what the problem would be with the Surface; the new terrain and Lidar rendering engine does tax the CPU, memory, and the graphics card a lot more than before; again, this may be something that you should take up with our support.

    Best regards,

    ~Jeff

Answers

  • GeoBobGeoBob Global Mapper User Posts: 26Trusted User
    I am experiencing similar poor performance issues with new 3D 'infinite' view in v18 as well. No longer able to use 3D viewer on MS Surface without near freeze-up. Always worked well in v17 and lower
  • kfroesekfroese Geotechnical Engineer Posts: 170Trusted User
    I see. I tried the 3D view with just the surface on and the rendering worked. I turned on some vector layers that had numerous points outside of the DEM, and the rendering slowed down significantly and did not reach the same level of detail in what I would consider to be a reasonable length of time. Perhaps some prioritizing of the rendering to concentrate on what is visible particularly for vector data? Or even an option to turn off the "infinite" view or limit it to data contained within the confines of the DEM area? I mean, I don't need it trying to render points 50 km off in the distance when my DEM covers an area only 8km x 7km.
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324Trusted User
    Hi kfroese,

    Sure - the terrain rendering does choose rendering quality based on distance from the camera. We're also planning on implementing a mode that's more like the GM17 operated: the 3D view only displays what's visible in the 2D view. It's issue #19550. No timetable on that yet, but we'll report back here when it's available.

    Best regards,

    ~Jeff
  • kfroesekfroese Geotechnical Engineer Posts: 170Trusted User
    But I don't think it is. If I add one layer with vector points far from the DEM surface of interest, the delay in rendering the 3D view when I zoom or pan is significantly longer.
    For example, I loaded a DEM that is about 12km x 10km (though not complete coverage in that area), a set of points showing photographs I took at a site within the DEM, and then a second set of points that are the waypoints recorded by my handheld GPSr during a three day tour of sites which included the site with the DEM. The GPSr points were within an area about 150km x 170km in which my DEM is near one corner. I recorded a video of the 3D rendering as I turned that GPSr layer on and off - you'll see a huge difference in rendering time and quality so it doesn't appear to be prioritizing what is near the camera because then it would be ignoring the points a 100km away. The video starts with the GPSr layer off and then it gets turned on almost immediately and then off again near the end. https://1drv.ms/v/s!AuuXpAG0lTNh0VNtqvZVcmGGUt5P

  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324Trusted User
    To be clear, I didn't say anything about prioritization, by which I take it you mean rendering data that's closest to the camera first.

    What I did say is that in general, the rendering process takes into account the distance from the camera, and tries to render the terrain imagery accordingly: locations far away from the camera don't need the full resolution of the terrain and imagery (since the user couldn't tell the difference), so it uses lower resolution data in that case, and higher resolution for nearer locations. However, higher level data may not be immediately available to the 3D viewer, but in the interest of responsiveness,  lower-resolution may be used initially, and be replaced by higher-resolution data as it becomes available.

    Basically, the idea is that the terrain renderer tries to fill in *some* data for the whole area as soon as possible, and will try to fill in with higher resolution data as needed over time, all the while maintaining responsiveness in the UI (you can clearly see this in the video, particularly in the second rendering cycle). As I say, it's a tricky balancing act (and I've simplified it in my description), and one that we aim to improve as we go along.

    With respect to the video, it does look as though the addition of the vector data layer influences the resolution at which the terrain is drawn, which is puzzling (unless it's related to the 3D setting "Draw 3D Vector Features Reflected on Terrain Surface"). It's also interesting that the tile sizes for the data are different between the two renderings (which may be a clue).

    In any case, thank you for providing the video. As I'm not the author of the terrain rendering code, I can't explain what it's showing, so I'll pass it along to get it looked at.

    ~Jeff
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324Trusted User
    Hi kfroese,

    If you're able to provide a sample workspace that exhibits the effect you're seeing, my colleague would sure like to be able to put it under the microscope. You can reach me at jeffh@bluemarblegeo.com.

    Thanks,

    ~Jeff
  • kfroesekfroese Geotechnical Engineer Posts: 170Trusted User
    Email with link to data files will be sent shortly.
  • kfroesekfroese Geotechnical Engineer Posts: 170Trusted User
    The latest release of GM v18 (18.0.3) had some nice-sounding words about the 3D view. However, I'm still having the same trouble - with vector data loaded that extends beyond the bounds of the LiDAR, the tiles are not fully drawn and left at a coarse resolution. If I turn off all vector layers, then the LiDAR does render correctly although the time to render appears to be slower than before as it keeps redrawing portions. In some cases, having a vector layer one (whose points are contained within the LiDAR bounds), some of the tiles never do get drawn leaving holes in the rendered surface.
    Overall, I'm disappointed in v18. The refreshed appearance and reorganization does not compensate for the cumbersome and buggy changes to the 3D view.
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324Trusted User
    Hi Ken,

    Just wanted to let you (and other folks in the forum) know that we have looked at the coarseness problem you brought up here, and we have an understanding of what's going on, though we don't have a timeline on a fix for that just yet (it wasn't part of 18.0.3). We'll be letting you know when that's ready.

    The 3D changes for version 18 were extensive, and also included many improvements in general data handling throughout Global Mapper as well, but we recognize that 3D is not yet as good as we'd like, and are continuing to work to improve it.

    Feedback like yours is important to us, and any further ideas and suggestions you or any other Global Mapper user might make are always welcome. 

    Best regards,

    ~Jeff
  • JeffH@BMGJeffH@BMG Global Mapper Developer Posts: 324Trusted User
    Oh, and for reference, the ticket number for the coarseness problem is #19707. We'll report back here once we have a fix.

    ~Jeff
  • Grumpy_98Grumpy_98 Global Mapper User Posts: 1
    Just installed the GM18 upgrade.  Noticed slightly less resolution of 1/3 arc second DEM data with GM18 3D relative to GM17 3D.  However, with the World Imagery overlay resolution gets progressively worse as I zoom in.  Eventually the display becomes unusable for my purposes.  Attached are snaps of Parachute Canyon, CO for comparison.  Note that the 2D view for both versions zoom in and maintain resolution.
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