CODEWITHSUNDEEP
matlabgraphics3d
Paul
Paul

Reputation: 21

Crop 3D Mesh with plane Cut in Matlab

I have made 3D analysis code and I want to split or crop 3D mesh into 2 parts with 2D plane, what i expected: the final result I need is to find out what are the nodes on the left side and the right side, what you see on the image below is the nodes of the 3D object (bumpy), Do you know what method or library I need to use to solve this problem? my problem Here is my data structure from the 2D plane: Column 1: Face Column 2: X coordinate Column 3: Y coordinate column 4: Z coordinate Column 5: Finite Element Value data structure . The data structure from the 3D mesh is containing the same data as the table above, Thanks so much!

We can know the plane XYZ Coordinates, so I tried to find by using <= to find the axis value is larger or smaller than the plane coordinates: find x,y,z 3D model coordinate is smaller than x,y,z cut plane coordinate [r] = find((Name_OT(:,1)>=x) & (Name_OT(:,2)>=y) & Name_OT(:,3)>=z);

the blue line is the plane, and the coloured one is the result from my code, the ideal result is the coloured nodes full, but what happened here the colour node has a big hole or gap

not good result

Upvotes: 0

Views: 428

Answers (1)

Argyll
Argyll

Reputation: 9875

You need to first decide whether you want to segment your data by a (linear) plane or not. If you prefer to keep a curved surface, please follow my earlier comment and edit your question.

To get a plane fit to the data for your cut, you can use fit.

Base on the plane, you can get a normal vector of the plane. That is reading coefficients of fit results and is in the documentation. Using that normal vector, you can rotate all your data so that the plane is normal to z axis. The rotation is matrix multiplication. From there, you can use logical indexing to segment your data set.

You can ofc also get the normal component of the data points relative to the plane cut and decide on a direction that way. You still need fit. From that point, it's basic matrix manipulation. An nx1 vector can multiply a 1xn vector in Matlab. So projectors can also be constructed from basic matrix manipulation. At a glance, this method is computationally inefficient.

Upvotes: 0

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