[運算] 3D中關於patch 用圓座標取點

看板MATLAB作者binjon (捨得斌~ 衝衝衝!!)時間11年前 (2014/05/20 16:24)推噓0(0推 0噓 3→)

留言3則, 2人參與討論串1/1

各位大大，小弟用Matlab轉檔案目前是用Matlab吃進來 stl 檔案然後在用圓座標去取上面的vertex 三角形的點。下面的範例是小弟嘗試用 (phi,theta,r)圓座標去取點，其中的phi和theta 為固定幾個角度，所以這邊是要取r 的值出來,最後再去描點(3dplot)再看結果。小弟方法分兩個步驟，第一個就是patch.face 規定的三個點圍成的平面和我所要描的 (phi,theta,r)對於圓心(0 0 0 )拉出來的線求交點。第二個就是用這個交點作線性規劃，找交點位於三點圍成的三角形之類，才是我判別點是在vertex 的平面上面，這樣就可以確定 r 值了。第二個線性規劃上面，我是用交點 vs.三角形分開為一條線和一個點作，如下圖右邊線為三角形的兩個點所成，然後交點只要在三角形內，則d1>d2 以此類推，我只要作三次都符合，就可以知道交點在這個face 內了。 d1 | 三角形上之點。-----------| d2 | 交點。-----| | 當然小弟是覺得這個方法很爛，目前抓的效果也沒很好不知道有沒有更聰明的辦法或是現成的func來確定3D下， "點是否在一個三角形內哩?" 感謝 !! (如果有人想try我這版本的code，請在跟我講哩，在給您詳細pattern之類的) input_pat = strcat('./data/',pattern,'.stl'); fv = stlread(input_pat); %% Render % The model is rendered with a PATCH graphics object. We also add some dynamic % lighting, and adjust the material properties to change the specular % highlighting. patch(fv,'FaceColor', [0.8 0.8 1.0], ... 'EdgeColor', 'none', ... 'FaceLighting', 'gouraud', ... 'AmbientStrength', 0.15); % Add a camera light, and tone down the specular highlighting camlight('headlight'); material('dull'); % Fix the axes scaling, and set a nice view angle axis('image'); %view([0 90]); view([-175 55]); size_pts = size(fv.vertices); number_points = size_pts(1); angle_C = zeros(1,number_points); angle_G = zeros(1,number_points); intensity = zeros(1,number_points); % All points here cart_points = fv.vertices; % All triangle series here face = fv.faces; %====================== % Debug figure,plot3(cart_points(1:end,1),cart_points(1:end,2),cart_points(1:end,3)); %====================== for i = 1:number_points [angle_C(i),angle_G(i),intensity(i)] = cart2sph(cart_points(i,1),cart_points(i,2),cart_points(i,3)); end %========= % Shift the Angle to fir IES format %============================== angle_C = angle_C*180/pi+180; angle_G = angle_G*180/pi+90; % G value: vertical angle, theta G_index = [0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00... 20.00 22.00 24.00 26.00 28.00 30.00 32.00 34.00 36.00 38.00... 40.00 42.00 44.00 46.00 48.00 50.00 52.00 54.00 56.00 58.00... 60.00 62.00 64.00 66.00 68.00 70.00 72.00 74.00 76.00 78.00... 80.00 82.00 84.00 86.00 88.00 90.00 92.00 94.00 96.00 98.00... 100.00 102.00 104.00 106.00 108.00 110.00 112.00 114.00 116.00 118.00... 120.00 122.00 124.00 126.00 128.00 130.00 132.00 134.00 136.00 138.00... 140.00 142.00 144.00 146.00 148.00 150.00 152.00 154.00 156.00 158.00... 160.00 162.00 164.00 166.00 168.00 170.00 172.00 174.00 176.00 178.00... 180.00]; % C value:horizontal angle, phi C_index = [90.00 105.00 120.00 135.00... 150.00 165.00 180.00 195.00 210 225.00 240.00 255.00 270.00 285.00... 300.00 315.00 330.00 345.00 0.00 15.00 30.00 45.00 60.00 75.00 90]; length_C = size(C_index); length_G = size(G_index); length_output = length_C(2)*length_G(2); output_intensity = zeros(1,length_output); intesity_test = 1; length_intensity = size(intesity_test); test_points = zeros(3,length_intensity(2)); test_points1 = zeros(3,200); tb_int1 = zeros(1,200); tb_int = zeros(length_intensity(2),number_points/3); %========================= % Debug sampled_x = zeros(1,number_points); sampled_y = zeros(1,number_points); sampled_z= zeros(1,number_points); inter_point = zeros(3,number_points/3); dist_point = zeros(1,number_points/3); thd_dist = 0.01; for i = 1:length_C(2) for j = 1:length_G(2) tmp_angle_C = (C_index(i) - 180)*pi/180; tmp_angle_G = (G_index(j) - 90)*pi/180; [test_points(1,intesity_test),test_points(2,intesity_test),test_points(3,intesity_test)] = ... sph2cart(tmp_angle_C,tmp_angle_G,intesity_test); for k =1:number_points/3 inter_point(:,k) = plane_line_intersection(cart_points(face(k,1),:),cart_points(face(k,2),:),cart_points(face(k,3),:),... 0,0,0,test_points(1),test_points(2),test_points(3)); % Linear Program a_flag_direction = (round(test_points(1,intesity_test))*round(inter_point(1,k))>=0)&&... (round(test_points(2,intesity_test))*round(inter_point(2,k))>=0)&&... (round(test_points(3,intesity_test))*round(inter_point(3,k))>=0); d_ori1 = dist(inter_point(:,k)',cart_points(face(k,1),:),cart_points(face(k,2),:)); d_ver1 = dist(cart_points(face(k,3),:),cart_points(face(k,1),:),cart_points(face(k,2),:)); d_ori2 = dist(inter_point(:,k)',cart_points(face(k,2),:),cart_points(face(k,3),:)); d_ver2 = dist(cart_points(face(k,1),:),cart_points(face(k,2),:),cart_points(face(k,3),:)); d_ori3 = dist(inter_point(:,k)',cart_points(face(k,1),:),cart_points(face(k,3),:)); d_ver3 = dist(cart_points(face(k,2),:),cart_points(face(k,1),:),cart_points(face(k,3),:)); if(d_ori1<(d_ver1-thd_dist))&&(d_ori2<(d_ver2-thd_dist))&&(d_ori3<(d_ver3-thd_dist))&&a_flag_direction %disp(['k=',int2str(k),',[x y z]= ',int2str(inter_point(:,k)')]); %disp(['P1= ',int2str(cart_points(face(k,1),:)),', P2= ',int2str(cart_points(face(k,2),:)),', P3= ',int2str(cart_points(face(k,3),:))]); dist_point(k) = sum(d_ori1+d_ori2+d_ori3); %disp(['dist_total = ',int2str(dist_point(k))]); end end [B1,index1] = max(dist_point); [tmp_C,tmp_G,tmp_intensity] = cart2sph(inter_point(1,index1),inter_point(2,index1),inter_point(3,index1)); output_intensity((i-1)*length_G(2)+j)= tmp_intensity; sampled_x((i-1)*length_G(2)+j)= inter_point(1,index1); sampled_y((i-1)*length_G(2)+j)= inter_point(2,index1); sampled_z((i-1)*length_G(2)+j)= inter_point(3,index1); end end figure,... plot3(sampled_x,sampled_y,sampled_z); -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 140.112.17.237 ※ 文章網址: http://www.ptt.cc/bbs/MATLAB/M.1400574240.A.C17.html