Fast Surface Reconstruction: Delaunay2.5D
Filed under: Algorithms, Computational Geometry, Graphics
Can a surface reconstructor be faster than a 2D mesher?
It is coming soon the Delaunay2.5D algorithm a new fast surface reconstructor. It is currently in a prototype state, still have to code pre-processor and post-processor parts. I will include it in my thesis.
This algorithm can deal with millions of points in a matter of a few second, it is basically faster than a 2d delaunay triangulation. For this reason I am also thinking about extend it to 2D and 3D triangulations.
More infos about the algorithm performances and how does it work will be given in future. At the time I only have this video demostration and a demo version.I was impatient to publish something about it 
.
Delaunay2_5D has been released here.
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Surface Reconstruction from Scattered Points Cloud: MyCrust Robust
It is now available on Matlab file exchange the robust and new version of MyCrust.
I hope you’ll enjoy it !
MyCrust take as input a 3D scatter points cloud and return a tight, manifold, triangulation.
Remember that crust algorithm needs a cloud representing a volume, so open surface may give inaccurate results. For example : a plane can not be triangulated, half-sphere is in doubt, a sphere with a small hole shoud be good.
The more points are given the best the surface will be fitted, of course in this case you would have to wait more and in the worst case a memory help error may occurs. The best results are obtained with more points in high curvature feature.
The old version did not ensure the output surface to be a manifold so it could be used only for graphical purpose. In the new one a tight, regular manifold is returned. It as outward normals orientation, after using this algorithm is very easy to get an STL file from a point cloud.
I added a manifold extraction tool that also correct the errors (slivers) generated by delaunayn during the initial tessellation.
Popularity: 49% [?]
3D Triangulated Models Collection
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Surface Reconstruction From Scattered Points Cloud: The Ball Fretting
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Basic Gear Design
Here you can find a simple tool to draw basic 3D spur gears feature. This tool is under development and collaboration is greatly appreciated. Several estention and improvements are possible. This can even be a basic brick for other graphical projects.
GearDesign returns the basic triangulated model of a 3D spur Gear. It requires in input a few standard parameter to insert in a structure. Here you can find the explanation of all parameters, for those who are not confident with mechanics but are curious to use this utility I suggest:
http://en.wikipedia.org/wiki/Gear
The INPUT parameters are:
- The Gear structure
Gear.m=1;%modulus
Gear.z=20;%number of teeth
Gear.Alpha=20;%Pressure angle degree
Gear.Addendum=1;%addendum/modulus ratio
Gear.Dedendum=1.25;%dedendum/modulus ratio
Gear.FaceWidth=10;%Face width
Gear.ShaftDiameter=4;%shaft diameter [mm]
Gear.numpoint=10;%number of points to approximate the tooth profile
Gear.t=[];%here will be stored the triangulation
Gear.p=[];%here will be stored points data - plotflag: turn on a plot of the designed gear
The OUTPUT parameter is the Gear structure but with filled:
- Gear.t (triangles)
- Gear.p (points).
Here is a an example:
Gear2.m=1;%modulus
Gear2.z=30;%number of teeth
Gear2.Alpha=20;%Pressure angle degree
Gear2.Addendum=1;%addendum/modulus ratio
Gear2.Dedendum=1.25;%dedendum/modulus ratio
Gear2.FaceWidth=4;%face width
Gear2.ShaftDiameter=8;%shaft diameter
Gear2.numpoint=10;%points to approximate the tooth profile
Gear2.t=[];%for the output
Gear2.p=[];%for the output
<p style="text-align: left;">% GEAR DESIGN
Gear2=GearDesign(Gear2,true);
A routine to experiment gears motion is provided.
For problems, questions, suggestions,:
Created: 18/01/2009
Last Update: 18/01/2009
Author: Giaccari Luigi
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Popularity: 58% [?]
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