The company I work for is considering getting into LADAR scanning to replace previous scanning . We received our first new LADAR scanner today, and will be doing a scan tomorrow. The device we are using generates a point cloud.
I am able to bring in a sample point cloud into Rhino 5 using the dot product rhino plugin, but I’m really not sure how to work with it.
It appears that I can not directly draw on a point cloud.
What I need to be able to do is extract 2d data from the point cloud. For example, if someone scanned the floor of a room, I want to be able to create an outline of a rug on the middle of the floor as accurately as possible. I need to be able to do this if the floor is not flat, or the equivalent on a vertical multi curved surface.
I really don’t want to have to turn the point cloud into a mesh or surface, I just want to see the details of the scan so that I can made a 2D drawing of the perimeters I need from it.
I want to draw the drawing using the point cloud as the reference.
Is what I am wanting to do possible, or do I need a different program to accomplish this?
What you want to achieve is possible. Do you have point snaps turned on? Some other commands to use are:
clippingplane (use multiples and back-to-back works quite well)
pointcloudsection
Hello - you should certainly be able to use all the regular drawing tools to draw ‘around’ or ‘through’ the point cloud but not on the point cloud. Point Osnap could be a blessing and a curse, depending on exactly what you want to do and how dense the cloud is.
Is there a specific drawing tool you want to use? It should all work, so I guess I need to know where it is failing…
What I need to draw is rather simple. I need to trace the perimeters of items or areas in the scan. These scans won’t always be flat or horizontal surfaces. I need to turn this traced perimeter into a flat 2d outline so a piece of material can be manufactured in that custom size.
There might be a U shaped area around a pipe coming out of the ground. I need to trace the outline of the U shaped area so we can cut a piece of material to fit this opening. We want to be as accurate as possible. The mechanical scanner we have works well, but is easy to break or damage and requires a high skill level to use. Very expensive. We have tried photogrammetry with targets, but that has been too slow.
I might have a similar situation on a wall with a complex curve on it. Where I might need a F shaped piece of material, just complex enough that hand measurements are not practical. I need to be able to trace that shape and project it(or unwrap it) accurately to cut a flat piece of material that will fit the area.
So lines, 4 point lines, circles, fillets, offsets on those lines.
Hello - this should just work if you start using the curve drawing tools - in Top, assuming the scan is aligned to the World, just start drawing - which ever tool makes sense - Polyline for example. If you do not snap to any points, the drawing will remain 2d on the construction plane; if you do want to snap to points, use the Project setting on the OSnaps toolbar to force all snaps to the CPlane.
If the scan is not aligned to the world or if there are skewed features, relative to the main views and planes, you may need to set custom CPlanes to particular features like walls etc. I can help with that if that is hanging you up.
I saw Cockroach, but right now I am running Rhino 5. We are starting to look at transitioning to 7, but it hasn’t happened yet. This might help it happen.
I was given our new scanner to play with. I scanned a Machinist’s rule laying on the floor, bought the point cloud into Rhino. Leveled it to the xy plane by eye, and traced it with a poly line. The error was about ± 1.2 mm.
I’m a little worried to have so much error over a 6 inch length, but to be fair, I have no idea if my point cloud was actually level or not. 1mm level of accuracy would be plenty fine if we can hold it across a much much larger area.
If this level of accuracy is repeatable, it is an amazing success for us.
Still we need to learn some best practices for working with point clouds. Is there a good tutorial (written or video) somewhere about working with point clouds?
@Hactual can you send us an example, either here or to tech@mcneel.com,(with a link back here in your comments)? I think this should be quite straightforward - with an example file I could tell for sure and -probably - get you pointed in the right direction.