I have some problems with mesh density of a few 3D solids. These solids are coming form Vulcan, a geology software, then I imported the mesh it in 3DS MAX to recreate the solids. Once the mesh is watertight, and without any issue, I would like to resample the mesh to reduce density.
Looking to a youtube movie, it looks that we simply have to export a PRT file from Krakatoa apps in 3DS and re sample the mesh in Sequoia. However, the export is only exporting a PRT file and not the SPRT, as we can see in the demo. Is there a reason for that. I set the mesh to an editable poly in 3DS.
When the video was recorded, Krakatoa was necessary to export a PRT (not SPRT) file to Sequoia. Sequoia supports reading PRT files and can convert them to SPRT for faster data access.
However, in the mean time we added a Surface Points object (5th icon from the left) which does the same as PRT Surface in Krakatoa, so you can simply import an OBJ, STL, PLY or XMesh of your geometry into Sequoia and turn it into points there.
Selecting the STL file, click ‘‘autoload’’, select the file in the box
Click ‘‘import’’
The computer run something for a few seconds…but nothing happen. What I am doing wrong ? The object can be open in several other softwares. I tried to change format to have a OBJ…but still the same.
You are doing it more or less right (the Batch menu approach is meant mostly for mass-importing dozens or hundreds of meshes - you can create a single Mesh Loader manually via the 4th green icon in the left toolbar when loading one file).
One possible issue could be that the mesh is very far away from the origin, and the viewport does not update to display it because it is outside of the view. Try selecting the Mesh Loader in the Document Explorer, then pressing the Z key (zoom extents), and then F5 (which forces an update of the current object).
If that does not help, take a look at the Log Window tab in the bottom right corner- there might be some useful messages there explaining what happened.
If you still have issues, you might want to send us a file to take a look and make sure we are reading it correctly. We have a dedicated Box account, please let me know if you need a place to upload a large file.
That works, you got it. I am very far away from the origin. So the file is displayed properly.
One more question…as the goal is to resample the mesh with lower density. Sorry for all those basics questions…
In the demo, you was working with points, and exporting it to a mesh where you can ‘‘play’’ with the density. What is the process to re-sample the mesh, if I do only have a mesh now ?
Just to add, that I created a new ‘‘surface point’’ and a new ‘‘region of interest’’ and a new ‘‘mesher’’. When I am trying to export, an error occur saying that there is no files linked.
When I look to mesh loader I got:
displayed points: 56 448
displayed faces: 18 816
Points in file : Nothing
Faces in file: Nothing
This is the difference I have noticed with your demo.
When creating new objects, you have to keep the previous object selected to create a connection automatically. Otherwise, you have to add the previous object manually.
So for example,
Create a Mesh Loader, pick your source file, update the Mesher.
With the Mesh Loader selected, create a Surface Points object - the Mesh Loader will appear on the mesh sources list. If it does not, you can press Add… and pick it by name.
With the Surface Points object selected, click the Point Region Of Interest icon - it will be created and connected to the Surface Points object (the Surface Points will appear on its list, otherwise you can use Add… to pick it).
With the Point Region Of Interest selected, click the Mesher icon - the Point ROI will appear on the Sources list of the Mesher.
You can then tweak the point count in the Surface Points object, adjust the Point ROI gizmo to include only a fraction of them if you want, then update the Mesher to create a mesh from the points. If you go to Export rollout in the Mesher, you can export an STL, OBJ, PLY or XMesh of the result even if you did not update in the viewport.
I will be creating a written tutorial with screenshots in the coming days, stay tuned!
That works I succeed. But the tutorial will be welcome.
One more question: Looking at the altered mesh, there is a kind of shell, meaning that the mesh has a thickness, and we can see one mesh superimposing the other one. Is that normal ? Is there a way to avoid this ?
Yes, this is the default meshing approach (producing a watertight shell around the points).
We have added the ability to remove one of the sides of the mesh, and conform the remaining polygons to the point cloud so they pass through the surface defined by the points. However, in some complex cases like cars etc., we cannot guarantee that the result will be watertight. You might have to process the mesh further in a 3D application after exporting.
Note that the workflow for single sided meshing is being finalized right now, so it is not completely exposed in the standard UI.
The basic workflow is this:
Right-click the Mesher in the Document Explorer and select “Cull Faces By Normal Similarity” (this step will be exposed as a checkbox in the Mesher UI in the very near future).
In the Mesher UI, check the “Flatten” option - this will add another operator called “Conform To Points”.
Update the mesh
You should now get a single-sided mesh (the outer part of the shell), which is then pushed back to the point cloud of the Surface Points object.