How can I extrude a 2D patch?

5 次查看（过去 30 天）

Radu Andrei Matei 2022-6-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1744760-how-can-i-extrude-a-2d-patch

评论： Radu Andrei Matei 2022-6-21

Hi, my objective is to have a gear profile like the one below extruded so that I can then convert the 3D gear into a STL file and send it to a 3D printer.

What I've tried to do, as the above are only discrete points, is to triangulate the surface using the delaunay function. That gave me the following result, which is of course bad:

By applying example 6 from https://www.mathworks.com/help/matlab/math/creating-and-editing-delaunay-triangulations.html I managed to get something like this, which is perfect:

The red gear was made with the delaunayTriangulation function with arguments (x,y,C) and eliminating all the triangles outside the gear profile. What I don't really get is how to create another identical patch but with different z coordinates and then join them together to get a 3D gear. I've been able to do it with the 3D delaunay function but what I get is an extrusion of the blue gear, like this:

Is there a way to filter out the triangles in the 3D triangulation outside the gear profile or to extrude the 2D red patch?

Thank you in advance guys :)

2 个评论
显示无隐藏无

KSSV 2022-6-21

Attach your data and code.

Radu Andrei Matei 2022-6-21

pointsPinion.txt

Hi, I'm going to attach the part of the code with which I do what I posted in my question. pointsPinion is a Nx3 matrix in which the first col contains x coords, the second y coords and the third z coords of the gear profile points. N depends on gear size. I'm gonna attach an example pointsPinion matrix in a txt file.

% This is from example 6 I mentioned. Idk how but it does what I want

nump = numel(app.pointsPinion(:,1));

C = [(1:(nump-1))' (2:nump)'; nump 1];

% This is the 2D constrained delaunay triangulation

dt = delaunayTriangulation(app.pointsPinion(:,1),app.pointsPinion(:,2),C);

% This is the unconstrained 3D delaunay triangulation

DT = delaunayTriangulation([app.pointsPinion(:,1);app.pointsPinion(:,1)],[app.pointsPinion(:,2);app.pointsPinion(:,2)],[app.pointsPinion(:,3);app.pointsPinion(:,3)+app.optiTrans.b]);

% What I do in DT is vertically concatenate two pointsPinion matrices, one with z = 0 and one with z = thickness

figure

tetramesh(DT) % Representing the 3D delaunay triangulation (bad 3D gear)

io = isInterior(dt); % Filter for points outside gear profile

patch('Faces',dt(io,:),'Vertices',dt.Points,'FaceColor','r') % This draws the red gear

请先登录，再进行评论。

请先登录，再回答此问题。