CloudCompare forum

First of all, Daniel, love your work and consistant work ethic and passion about your program, its the best Ive ever experianced. I could gush for pages.

I have a challanging modeling process. We have point clouds of electrical substations! The first time through I subsampled (bad idea), after that I used some of the other processes and got it going pretty well. (Exported out the model without ground, density filtered, subsectioned) Unfortunately after the mesh there was about 30 million faces! I simplified that to 1% to get the model to a workable fps, but by then after my botched rushed first learning attempt I had a day to sit down and look through the program to optimize the process.

Before I used poisson on subsections of the model with similair densitiez and then combined them after using the density filter on the mesh (bad normals, crap everywhere)

Now I looked at the Ransac result and its perfect in most regards (everything but the main transformer and the control house are cylinders!)

What would be a recommendation for replicating the ransac result, but as a mesh. I tried to use poisson, but I didnt have time to up the octree past 8. Ive been reading other forums and I think Ill be able to generate half decent normals now, but I cant seem to get an appropriately sized cylinder to mesh.

Any tips?

1) For your first attempt (with 30 M. faces) have you used Poisson? Because the number of triangles mainly depend on the octree level, not the number of input points.

2) What do you mean by 'replicating the ransac result as a mesh'?

Ransac outputs several primitives, and for each primitive you got the corresponding points (as a point cloud) and the primitive (which is in fact a small triangular mesh). For each primitive you can choose the 'drawing precision' (how much triangles are used to represent the primitive). But that's all. And sadly you can't merge the primitives as a single mesh yet (well not directly... if you select all of them, you can save them as a single OBJ file, and then reload it to get a single mesh). And another trick to select all primitives at once is to use the 'Select children by type and/or name' when right-clicking on the main Ransac output group.

Don't hesitate to post snapshots also ;)

TLDR: Bradw, Ransac is in fact a triangulated mesh!

New Question: Can I keep a colorized data set when I use Ransac? I know it randomly assigns colors, maybe I can recolorize it later in the process. (I'll look into this when the data is done loading, take a few hours normally).

1) Yeah the first go was Poisson.
2) Ransac did great at shape detection and made really fantastic representative surfaces in the cloud. I am trying to make a 3d model that looks like those colored shapes that ransac created!

What I didn't know was that the primitive is in fact a triangulated mesh. The model is about 60 gb when it's all broken up so when it gets done loading I'll find out what I can do with that. If it is in fact a model with surfaces I think I'll yell loud enough to be somewhat satisfied but not enough to disturb everyone in the office. :)

I have a pretty thorough documentation on the process, unfortunately this is connected to a spur of the moment project so the data is a clients and not my own :( Hopefully I'll convince them to let me use a site as an example and I can make some youtube videos/customer tutorials explaining cloud compare, giving what I learned, and my company's process of model making from LIDAR.

Great tips! As a follow up question, I load my data as point clouds from individual scans, then I have to hand select and merge them all together. The clouds are already registered, is there a way I can load and merge them easily? I select all to upload, but after the upload I couldn't get them all in one folder to select all, I swear I did it that way the first time through but I couldn't replicate it! (Select all feature for files under different folders?)

I think you can simply use the 'CTRL+A' shortcut to select everything in the DB tree, and then use the 'Edit > Merge' tool.

If it doesn't work I have another solution but it's more tricky (so I'll wait for your feedback first ;).

And for the colors, I think that Ransac doesn't let you chose it. The primitives (meshes) can't be colored easily, and the subsets of points corresponding to each primitive is assigned the same color as the primitive (overwriting the original color).

And I think I wrongly said that you couldn't merge the primitives in CC. I believe it's now possible (I just hope it won't crash if you have too many of them ;).