Descartes Point Cloud Presentation

I'll verify why we cannot use circles as templates for the model by section tool.

In the meantime, since you are trying to extract cylinders, did you have a look at the "Fit Cylinder" tool?

This tool is specifically designed to extract cylinder elements from point cloud. It only takes one click to extract a cylinder.

Here is some more information on the tool:
communities.bentley.com/.../fit-cylinder-improvement
communities.bentley.com/.../10570

HTH,
Pascal

I thought about using the extract cylinder tool, the only problem being that the whole reasoning for trying to use this software is because about halfway down the pipe there is a section that is blow out and the client is trying to determine the volume of the exploded area as it has been blown for many years and due to high water pressure it has created quite a large whole in the concrete and the model by section seems to be the, I hesitate to say, "best" approach but possibly will provide the most accurate volume calculations given an small distance between sections.

Another problem I am having now is that I essentially need two shapes within my template but not for every section, but for either end of the blowout since there is remaining pipe that extrude into the whole. I am thinking what Ill have to do is do 3 separate models, convert them to meshes and then join them. But any input would be great as I have about 20 hours of experience with Microstation/Descartes.

Hi Curtis,

Which Fit Cylinder mode are you using? The one point or the three points? Have you tried both?

Also are the cylinders have missing or occluded parts? The Fit Cylinder should be working even if the cylinder is not completely model, but maybe this is the problem?

Also does the cylinder are represented with a great density of points? If the density of points is too low the 1 point fit cylinder could fail. The three points mode should be used instead.

HTH,

Mathieu

I did in fact try both. The density of the point cloud is pretty high. It is clearly discernible as a pipe. Simply, any tool I select and hover over a point on the point cloud it gives me the little yellow x and says this object isn't valid for this tool.

With that being said, the pipe really isn't the difficult part. For the most part the pipe is in tact, so modeling it by section still only takes a few minutes. The problem is where the pipe has burst, over the years, has created a large empty void in the surrounding ground and concrete. Due to the nature of it, it is a large irregular shaped object, so modeling it by section takes a b-spline with a huge amount of vertices and it requires to be sectioned about every 2-4 inches. So an object approximately 150 cu ft., sectioned ever 2-3 inches, changing 50+ vertices each time the template is copied to the new section takes a huge amount of time. Not saying I didn't do it, but I feel that this should be an issue that has been addressed previously and there are many ways to expedite the process.

As I said before, I am very new to Bentley Microstation/Descartes and wasn't sure. It seems by now that between this company and AutoCad that a solution to creating surfaces/solids from point cloud data should be a breeze. I know that AutoCad's weakness seems is the inability to read in such large files where Bentley does it no problem.

Also, I keep hearing about this drape command and it seems like that would be a solution, but I have no idea how it works or how to operate the tool. If anyone could point me in the direction of a "good" tutorial that would be awesome.

Hi Curtis,

" Simply, any tool I select and hover over a point on the point cloud it gives me the little yellow x and says this object isn't valid for this tool. "

Very strange, is your point cloud attached to the Point Clouds manager dialog as a POD file? The Fit Cylinder tool works only with POD file attached to the Point Cloud manager dialog.

As for modelling advice it would be nice if you could post a picture of what you are trying to model?

Thanks,

Mathieu

Yes it is attached as a .pod.  It converts it to a .pod file when you load the file.

This is an image of what I was able to create after about 12 hours of modeling by section and copying over a template.

Hi Curtis,

I think the purple object should modeled with surface reconstruction algorithm. Descartes has no such function to do that. You could try isolating the points corresponding the purple surface and creating a MicroStation mesh. Not sure about the result though.

The Fit Cylinder should work well on the undamaged pipe section.

HTH,

Mathieu

Hi Curtis,

I think the purple object should modeled with surface reconstruction algorithm. Descartes has no such function to do that. You could try isolating the points corresponding the purple surface and creating a MicroStation mesh. Not sure about the result though.

The Fit Cylinder should work well on the undamaged pipe section.

HTH,

Mathieu