hello 

I'm doing an experiment based on the "VolumeBrush" example. I created a 3D model and exported it in "stl" and after that I modified the sketch to import this model, but when I click to continue drawing the model disappears. 

thanks for everything

2. import toxi.geom.*;
3. import toxi.geom.mesh.*;
4. import toxi.volume.*;
5. import toxi.math.waves.*;
6. import toxi.processing.*;
7. 
   
8. import processing.opengl.*;
9. 
   
10. int DIMX=64;
11. int DIMY=64;
12. int DIMZ=64;
13. 
    
14. float ISO_THRESHOLD = 0.1;
15. Vec3D SCALE=new Vec3D(1, 1, 1).scaleSelf(100);
16. 
    
17. VolumetricSpace volume;
18. VolumetricBrush brushRedondo;
19. VolumetricBrush brushQuadrado;
20. IsoSurface surface;
21. 
    
22. //WETriangleMesh mesh;
23. 
    
24. WETriangleMesh importMesh;
25. TriangleMesh exportMesh;
26. WETriangleMesh mesh;
27. 
    
28. AbstractWave brushSize;
29. 
    
30. boolean brushRedondoOn = true;
31. boolean brushQuadradoOn = false;
32. 
    
33. boolean isWireframe=false;
34. boolean doSave=false;
35. 
    
36. float currScale=4;
37. float density=0.5;
38. 
    
39. ToxiclibsSupport gfx;
40. 
    
41. void setup() {
42.   size(1024, 768, OPENGL);
43.   hint(ENABLE_OPENGL_4X_SMOOTH);
44.   
45.   strokeWeight(0.5);
46.   volume=new VolumetricSpaceArray(SCALE, DIMX, DIMY, DIMZ);
47.   brushRedondo=new RoundBrush(volume, SCALE.x/2);
48.   brushQuadrado=new BoxBrush(volume, SCALE.x/2);
49.   brushSize=new SineWave(0, 0.1, SCALE.x*0.07, SCALE.x*0.1);
50.   surface=new ArrayIsoSurface(volume);
51.   importMesh = (WETriangleMesh) new STLReader().loadBinary(sketchPath("scribble1380492459.stl"), STLReader.WEMESH);
52. 
    
53.   mesh=new WETriangleMesh();
54. 
    
55.   exportMesh=new TriangleMesh();
56.   
57.   gfx=new ToxiclibsSupport(this);
58. }
59. 
    
60. void draw() {
61. 
    
62.   if (brushRedondoOn) {
63.     brushRedondo.setSize(brushSize.update());
64.   }
65.   if (brushQuadradoOn) {
66.     brushQuadrado.setSize(brushSize.update());
67.   }
68.   Vec3D mousePos=new Vec3D((mouseX-width/2)*0.5, (mouseY-height/2)*0.5, sin(frameCount*0.05)*SCALE.z*0.5);
69.   if (mousePressed) {
70. 
    
71.     if (brushRedondoOn) {
72.       brushRedondo.drawAtAbsolutePos(mousePos, density);
73.     }
74.     if (brushQuadradoOn) {
75.       brushQuadrado.drawAtAbsolutePos(mousePos, density);
76.     }
77. 
    
78. 
    
79.     volume.closeSides();  
80.     surface.reset();
81.     importMesh.addMesh(mesh);
82.     surface.computeSurfaceMesh(importMesh, ISO_THRESHOLD);
83.     
84.   }
85.   
86.   if (doSave) {
87.       // save mesh as STL or OBJ file
88.       surface.computeSurfaceMesh(exportMesh, ISO_THRESHOLD);
89.       exportMesh.saveAsSTL(sketchPath("scribble"+(System.currentTimeMillis()/1000)+".stl"));
90.       doSave=false;
91.     }
92.     
93.   background(128);
94.   translate(width/2, height/2, 0);
95.   lightSpecular(230, 230, 230);
96.   directionalLight(255, 255, 255, 1, 1, -1);
97.   shininess(1.0);
98.   rotateX(-0.4);
99.   rotateY(frameCount*0.05);
100.   scale(currScale);
101.   beginShape(TRIANGLES);
102.   if (isWireframe) {
103.     stroke(255);
104.     noFill();
105.   } 
106.   else {
107.     noStroke();
108.     fill(255);
109.   }
110. 
     
111.   gfx.mesh(importMesh);
112.   noFill();
113.   stroke(255, 0, 0);
114.   gfx.sphere(new Sphere(mousePos, brushSize.value), 20);
115. }
116. 
     
117. void keyPressed() {
118.   if (key=='-') { 
119.     currScale=max(currScale-0.1, 0.5);
120.   }
121.   if (key=='=') { 
122.     currScale=min(currScale+0.1, 10);
123.   }
124.   if (key=='w') { 
125.     isWireframe=!isWireframe; 
126.     return;
127.   }
128.   if (key=='s') { 
129.     doSave=true; 
130.     return;
131.   }
132.   if (key>='1' && key<='9') {
133.     density=-0.5+(key-'1')*0.1;
134.     println(density);
135.   }
136.   if (key=='0') { 
137.     density=0.5;
138.   }
139.   if (key>='a' && key<='z') {
140.     ISO_THRESHOLD=(key-'a')*0.019+0.01;
141.   }
142.   if (key=='g') {
143.     if (brushRedondoOn) {
144.       brushRedondoOn = false;
145.       brushQuadradoOn = true;
146.     }
147.     else {
148.       brushRedondoOn = true;
149.       brushQuadradoOn = false;
150.     }
151.   }
152.   if (key == 'l') {
153.     new LaplacianSmooth().filter(mesh, 1);
154.   }
155. }