Rendering and working with PointClouds is very very poor?

My Experience with Point Clouds Rendering in uStation v8i SS3

All across Bentley.com is read about pointools, Descartes and "Visualization" of point clouds... But I dont really see HOW to do that ANYWHERE?

I mean.. I can load a pointcloud in uStation (SS3 user here) but its dumber than dumb when it comes to controlling!? (Or I am!)

So whats getting me all worked up:

I can NOT crop/mask the pointcloud in realtime using shapes?
I can mask it using something like a block only!?

It does NOT respond to lighting?
EDIT: It does produce shadows from sunlight it seems. Just as you vould expect any 2D geometry to do. It does NOT care about lineweight though.

It does NOT use the full resolution?
If my view is set to show 20% of the points, then the render is just as bad! But even at 100% in a VIEW, Not all points are showing!
Also, the resolution rendered depends on the size of the VIEW being rendered!! Rendering with AA does not up the point count, only increasing the view size seems to.

It does NOT render intelligent in any way?
Points are rendered as tiny specs of dust only!
I would expect at least an estimated closed surface by connecting close points, or at least the tools to do it swiftly. Respecting linescale goes without saying! (does not do that)
It does respect "depth-of-field" but produces artifacts. Black dots with white "ghost".
It does respect "contour shading", but.. thats.. I mean.. dots with black outlines..

I can NOT reclassify points using shapes/solids?
I can reclassify by drawing a shape only!? And then I have to export the entire pointcloud which seems to take ALOT of time.. A serious lot of time. 300MB (4.5million xyz's) takes +10 minutes!! This is not rocket science and needs NO calculations of ANY kind, its just a list of coordinates that needs to be either written or skipped (as all we can do is filter by classification!) - This is really bad! - I wonder what happens when we begin working on our multi gigabyte sets?!!

Scalable Terrain Model (a Descartes thingy) can NOT make a useful model from a point cloud!?
Descartes is simply using the XYZs to make a top-down mesh of triangles between ALL the points (as seen from space mind you) Which is pretty much the same as a DTM, except it looks like poop because it automatically lowers resolution!!?? This STM does not respect holes cut into the pointcloud. You can exclude points by shapes in the STM, but the holes are filled when viewing and rendering the STM!! So you cannot use this with any other geometry!?

How hard can it be to make a surface and access that dynamically instead of the points? Just make smallest triangles. And maybe get fancy and reduce geometry somehow; if sidelength is too long then exlude triangle. Or even reduce by neighbouring surface angles.. Or use a tree structure.. ;o)

I am new to working with pointclouds, but have known and read about them.

Please help me achieve (at least) a decent rendering:

Assuming a ginormeous classified, colored pointCloud.

I speculate I need some of the following questions answered, but ANY hints/ideas that work fast and efficient is much appreciated.
The goal is that we dont model, we dont fix.. We clip the pointcloud, add our project, and render!

A. Preferably I need a procedure that just clip and filter the pointCloud on-the-go. So I can show anything except the ground as points.

B. Make a "2½D" regular triangulated (not autoscaled as that clearly doesnt work in renderings) DTM that respects the holes in the pointcloud, based on a classification filter.

C. Perhaps a procedure to split the pointCloud and matching surface into smaller managable "tiles" that will cull when rendering?

PLEASE help me "Get more value out of the pointcloud data"... please... PLEASE!

/Torben

p.s. This has been and will be heavily edited as I digg deeper.. Thus responses after this post might not reflect the current text.

p.p.s. http://www.isprs.org/proceedings/XXXVI/part5/paper/RABB_639.pdf - Techniques to automate the generation of surfaces from a pointCloud.

Parents
  • Hi Torben,

    Yes while point clouds are often jaw dropping they generally require post processing steps (e.g. : extraction, transformation, etc...) before something useful can be done with them.

    This is quite similar to raster data (e.g. : even if you see the pixels describing road you cannot do much with it without modeling the road with some kind of vector).

    Some of your items are CRs and so I will forward your post to product manager responsible for point cloud.

    As for the resolution this is normal that the full resolution is not available all the time. This is the same for raster and STM, two others kind of data that can contains billions of pixels/points. Certainly displaying the full resolution on a computer screen having only a few millions pixels is absolutely not useful and would certainly kill the visualization performance.

    The new Scalable Terrain Model is only a 2.5D terrain and thus should only by created from 2.5D data like aerial point cloud with points being classified as terrain or post-processed to remove any above ground features.

    Finally I would suggest that you check the WIKI web pages describing the new functionalities in Descartes SELECTSeries 3 (see the SELECTSeries 3 section on communities.bentley.com/.../bentley-descartes.aspx).

    Thanks,

    Mathieu



Reply
  • Hi Torben,

    Yes while point clouds are often jaw dropping they generally require post processing steps (e.g. : extraction, transformation, etc...) before something useful can be done with them.

    This is quite similar to raster data (e.g. : even if you see the pixels describing road you cannot do much with it without modeling the road with some kind of vector).

    Some of your items are CRs and so I will forward your post to product manager responsible for point cloud.

    As for the resolution this is normal that the full resolution is not available all the time. This is the same for raster and STM, two others kind of data that can contains billions of pixels/points. Certainly displaying the full resolution on a computer screen having only a few millions pixels is absolutely not useful and would certainly kill the visualization performance.

    The new Scalable Terrain Model is only a 2.5D terrain and thus should only by created from 2.5D data like aerial point cloud with points being classified as terrain or post-processed to remove any above ground features.

    Finally I would suggest that you check the WIKI web pages describing the new functionalities in Descartes SELECTSeries 3 (see the SELECTSeries 3 section on communities.bentley.com/.../bentley-descartes.aspx).

    Thanks,

    Mathieu



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