Keeping only internal points of a cylindrical shape

Discuss all Cyclone 3DR related issues here.
Post Reply
User avatar
Mike H
I have made 20-30 posts
I have made 20-30 posts
Posts: 26
Joined: Thu Aug 27, 2015 5:30 pm
Full Name: Michael H
Company Details: CFM
Company Position Title: Senior Surveyor
Country: Canada

Keeping only internal points of a cylindrical shape

Post by Mike H »

I have a scan of a screen that has voids that allow scan points to pass through as noise data. Is there an easy way to clean away the noise outside of the cylinder and keep only the inside points?

We have the tank module to 3dReshaper which works great on solid tanks but I cannot find a good way to clean away noise to only leave the inside face.ImageImage

User avatar
gilles_3DR
V.I.P Member
V.I.P Member
Posts: 202
Joined: Mon Dec 08, 2014 11:41 am
Full Name: Gilles Monnier
Company Details: Hexagon
Company Position Title: 3DR Technical Manager
Country: France
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 9 times

Re: Keeping only internal points of a cylindrical shape

Post by gilles_3DR »

Hi Mike,

in order to split the points inside a cylinder from those outside the cylinder, just follow the following steps:
  • create the cylinder
  • select the point cloud and the cylinder
  • launch the command Cloud / Separate with object
  • select the option "Separate the inside and the inside"
  • choose which points you want to keep (inside, or outside, or both)

User avatar
Mike H
I have made 20-30 posts
I have made 20-30 posts
Posts: 26
Joined: Thu Aug 27, 2015 5:30 pm
Full Name: Michael H
Company Details: CFM
Company Position Title: Senior Surveyor
Country: Canada

Re: Keeping only internal points of a cylindrical shape

Post by Mike H »

Gilles,

I have no way of creating an accurate best fit cylinder since the cloud still has noise data, it's hard to explain. Using the attached photo of the object I scanned, I'm looking to show the deformation of just the inside face of the cylindrical object(washer screen). I'm getting noise data that is extending outside the object that is giving me trouble creating a best fit cylinder and an accurate mesh.

User avatar
gilles_3DR
V.I.P Member
V.I.P Member
Posts: 202
Joined: Mon Dec 08, 2014 11:41 am
Full Name: Gilles Monnier
Company Details: Hexagon
Company Position Title: 3DR Technical Manager
Country: France
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 9 times

Re: Keeping only internal points of a cylindrical shape

Post by gilles_3DR »

ok!
then, maybe you can try:
  • create a cylinder by clicking a few points in the inside of the screen (using construct / Cylinder / Draw)
  • use this cylinder to keep only the points close to the cylinder using cloud / Separate with object (using "separate using a tolerance" option)
  • finally, use the same cylinder to keep only the points which local normals are similar to the local normal of the cylinder using cloud / Separate with object (using "separate using object orientation", use cloud estimated normal)
the final step will work if you have enough points locally in the parts you want to keep

User avatar
Phill
V.I.P Member
V.I.P Member
Posts: 619
Joined: Wed Feb 06, 2008 7:19 am
Full Name: Phillip Nixon
Company Details: SKM
Company Position Title: Surveyor
Country: Australia
Location: Sydney
Has thanked: 2 times
Been thanked: 22 times

Re: Keeping only internal points of a cylindrical shape

Post by Phill »

Mike

Gillies seem to have a pretty good workflow there. An alternative might be

1. Rough in the cylinder so you've got some numbers for unfurl
2. Use unfurl to make the cylinder into a flat plane
3. Import flat cylinder back into cyclone
4. Use region grow -> smooth surface
5. Use insert copy of objects point to separate out the cylinders points
6. Export and Refurl
7. Make your magic in reshaper

Alternatively you might be able to use las tools to make a ground surface once you have unfurled the data, which would sample the low points (requires a bit of mucking around with coordinate systems of course)

These are the options I'd be looking at if it was my job.

See link to unfurl/refurl post
viewtopic.php?f=23&t=4154&start=30

Lastools
https://rapidlasso.com/lastools/lasground/

Cheers

Phill

User avatar
Mike H
I have made 20-30 posts
I have made 20-30 posts
Posts: 26
Joined: Thu Aug 27, 2015 5:30 pm
Full Name: Michael H
Company Details: CFM
Company Position Title: Senior Surveyor
Country: Canada

Re: Keeping only internal points of a cylindrical shape

Post by Mike H »

Phill wrote:Mike

Gillies seem to have a pretty good workflow there. An alternative might be

1. Rough in the cylinder so you've got some numbers for unfurl
2. Use unfurl to make the cylinder into a flat plane
3. Import flat cylinder back into cyclone
4. Use region grow -> smooth surface
5. Use insert copy of objects point to separate out the cylinders points
6. Export and Refurl
7. Make your magic in reshaper

Alternatively you might be able to use las tools to make a ground surface once you have unfurled the data, which would sample the low points (requires a bit of mucking around with coordinate systems of course)

These are the options I'd be looking at if it was my job.

See link to unfurl/refurl post
viewtopic.php?f=23&t=4154&start=30

Lastools
https://rapidlasso.com/lastools/lasground/

Cheers

Phill
Thanks Phil. I was thinking of smooth surface but it didn't work on a cylinder. I will use the unroll in CloudCompare, smooth surface in Cyclone and export surface pts to 3dreshaper.

Post Reply

Return to “Leica Cyclone 3DR”