Delete Isolated points in Cloud points

Forums Technical Discussion Delete Isolated points in Cloud points

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magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Jan. 29, 2017 2:10 p.m.

Hi everyone,

I’m new in Houdini and I try to do some geometry from points cloud.

First I wanna clan my point cloud from Alembic file because I have some points wrong, isolate than another points so I need to delet this point and then try to connect this points to create a geometry.

Now I was trying to create a group and then delete it, but I don’t know what expression I need to use in Attribute Create or Attribute Wrangle, to select the isolate points with some dynamic value.

I this picture you can see my points.

Thanks


Enivob: Member; 2657 posts; Joined: June 2008; Offline

Jan. 30, 2017 11:30 a.m.

Just select the ones you do not want in the viewport and press the delete key. This will generate a Blast node with the point numbers in the pattern field. Those numbers can be used for further processing as well. Or copy those numbers into the Group field for a group node to make them a group.

Using Houdini Indie 20.5
Windows 11 64GB Ryzen 16 core.
nVidia 3060RTX 12BG RAM.


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Jan. 30, 2017 8:27 p.m.

Thanks Enivob,

I can't select all points they are in all the cloud, like 29 millions in total. I need to create a smart selection by radius and try to select the isolated points in all of the cloud. I have small zones, I can't access.

Another idea?

Thanks everybody


sepu: Member; 473 posts; Joined: Feb. 2012; Offline

Jan. 30, 2017 8:34 p.m.

There is definitely more procedural way to delete points.. it will be helpful if you post your file.


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Jan. 31, 2017 12:58 a.m.

Hi! sure
Hi this is an example.

Attachments:
TestPoints_02.hipnc (80.9 KB)


sepu: Member; 473 posts; Joined: Feb. 2012; Offline

Jan. 31, 2017 1:12 a.m.

You need to press the lock btn to get the geo


Enivob: Member; 2657 posts; Joined: June 2008; Offline

Jan. 31, 2017 8:41 a.m.

Just do a group by bounding using the sphere option and that will get you all points within a certain radius. Same workflow applies. Delete or Blast them after you have the group.

Using Houdini Indie 20.5
Windows 11 64GB Ryzen 16 core.
nVidia 3060RTX 12BG RAM.


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Jan. 31, 2017 12:56 p.m.

I'm sorry I thought houdini attached it automatically.

Thanks Sepu, I attached the file again.

Edited by magolalipson - Jan. 31, 2017 12:57:23

Attachments:
TestPoints_02.hipnc (353.7 KB)


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Jan. 31, 2017 4:40 p.m.

Maybe with this example is easier to understand!
I can't select the points in the air only if I make a selection as a radius from every particle, if this particle doesn’t find a another particle it’s one of I want to delete.

This is the reason I think I need to use Attribute Create or Attribute Wrangle o group I’m not sure.
Thanks if someone any idea.

Attachments:
Tetera_Geo.hipnc (3.5 MB)


tamte: Member; 9241 posts; Joined: July 2007; Offline

Jan. 31, 2017 11:46 p.m.

try Fuse Sop
check Keep Unused Points and play with the distance

EDIT: I read it wrong:
try doing this in point wrangle:

int pts[] = nearpoints(0, @P, chf("radius"),2);
if (len(pts)==1){
    removepoint(0,@ptnum);
}

Edited by tamte - Jan. 31, 2017 23:54:10

Tomas Slancik
CG Supervisor
Framestore, NY


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Feb. 2, 2017 3:31 p.m.

Hi Tamte,

Your syntax was an advance thanks, it’s works!! Now I see I need one more think?
I need only one network of points (the biggest), so I need to see only a points who are connected with another point (radius 2). I don’t want a net point more far than radius value.
It’s hard to explain.
Do you recommend me some tutorial for learn how can I read this kind of syntax’s in Vex?
Thanks People


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Feb. 2, 2017 4:23 p.m.

the file

Attachments:
Tetera_Geo3.hipnc (4.7 MB)


magolalipson: Member; 12 posts; Joined: Jan. 2017; Offline

Feb. 2, 2017 4:23 p.m.

the points

Attachments:
pointwrangle.jpg (1.2 MB)


Adetayo: Member; 2 posts; Joined: Jan. 2020; Offline

June 5, 2021 12:53 p.m.

Just add a facet node, click remove inline points and play with the distance.
You welcome.

Edited by Adetayo - June 5, 2021 14:17:56

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