kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo_bernardo@xxxxxxxxx>]

Due to the combination of very large scale factors and very small scale factors in the exported VRML file, truncation errors in VRML viewers (whitedune and lookat) caused problems; for example whitedune would render correctly when exported in mm but gives bad results when exporting to inch or meter.  I have changed the code to scale the point coordinates rather than specifying a global scale + counteracting local scales and this appears to solve the problem.  When tested with the pic_programmer demo, the resulting file size was smaller by almost 2MB (~7.7MB rather than ~9.5MB) due to space saved in writing the text representation of coordinates.

Other changes made:
1. removed unnecessary translation/rotation/scale parameters within the VRML Transform block
2. corrected the URL file syntax

I am aware of at least one bug but it is one that requires some thought before deciding how to address it: if relative filenames are used, the URL points to invalid relative locations. I believe relative file URLs should only be allowed when the 3D models are copied to a directory (this allows people to give their board VRML model to others), and absolute file URLs should be used when the models are not being copied.

There is also a problem with thru-hole pads; for the resistors and diodes (in pic_programmer) it seems pads are rendered, but for the DILs only the first pad is rendered. I haven't had time yet to look into this.

Regards,
Cirilo

=== modified file 'pcbnew/export_vrml.cpp'
--- pcbnew/export_vrml.cpp	2013-01-12 10:35:08 +0000
+++ pcbnew/export_vrml.cpp	2013-01-13 09:18:58 +0000
@@ -303,16 +303,14 @@
 
 
 static void write_triangle_bag( FILE* output_file, int color_index, //{{{
-                                const TriangleBag& triangles )
+                                const TriangleBag& triangles,
+                                double boardIU2WRML )
 {
     /* A lot of nodes are not required, but blender sometimes chokes
      * without them */
     static const char* shape_boiler[] =
     {
         "Transform {\n",
-        "  translation 0.0 0.0 0.0\n",
-        "  rotation 1.0 0.0 0.0 0.0\n",
-        "  scale 1.0 1.0 1.0\n",
         "  children [\n",
         "    Group {\n",
         "      children [\n",
@@ -379,12 +377,15 @@
                      i != triangles.end();
                      i++ )
                 {
-                    fprintf( output_file, "%g %g %g\n",
-                             i->p1.x, -i->p1.y, i->p1.z );
-                    fprintf( output_file, "%g %g %g\n",
-                             i->p2.x, -i->p2.y, i->p2.z );
-                    fprintf( output_file, "%g %g %g\n",
-                             i->p3.x, -i->p3.y, i->p3.z );
+                    fprintf( output_file, "%.8g %.8g %.8g\n",
+                             i->p1.x * boardIU2WRML, -i->p1.y * boardIU2WRML,
+                             i->p1.z * boardIU2WRML );
+                    fprintf( output_file, "%.8g %.8g %.8g\n",
+                             i->p2.x * boardIU2WRML, -i->p2.y * boardIU2WRML,
+                             i->p2.z * boardIU2WRML );
+                    fprintf( output_file, "%.8g %.8g %.8g\n",
+                             i->p3.x * boardIU2WRML, -i->p3.y * boardIU2WRML,
+                             i->p3.z * boardIU2WRML );
                 }
             }
             break;
@@ -1098,7 +1099,8 @@
 static void export_vrml_module( BOARD* aPcb, MODULE* aModule,
                                 FILE* aOutputFile,
                                 double aVRMLModelsToBiu,
-                                bool aExport3DFiles, const wxString & a3D_Subdir )
+                                bool aExport3DFiles, const wxString & a3D_Subdir,
+                                double boardIU2WRML )
 {
     // Reference and value
     export_vrml_text_module( aModule->m_Reference );
@@ -1206,9 +1208,9 @@
         RotatePoint(&offsetx, &offsety, aModule->GetOrientation());
 
         fprintf( aOutputFile, "  translation %g %g %g\n",
-                 (double) (offsetx + aModule->m_Pos.x),
-                 - (double)(offsety + aModule->m_Pos.y),    // Y axis is reversed in Pcbnew
-                 offsetz + layer_z[aModule->GetLayer()] );
+                 (double) (offsetx + aModule->m_Pos.x) * boardIU2WRML,
+                 - (double)(offsety + aModule->m_Pos.y) * boardIU2WRML,    // Y axis is reversed in Pcbnew
+                 offsetz + layer_z[aModule->GetLayer()] * boardIU2WRML);
 
         fprintf( aOutputFile, "  scale %g %g %g\n",
                  vrmlm->m_MatScale.x * aVRMLModelsToBiu,
@@ -1216,18 +1218,19 @@
                  vrmlm->m_MatScale.z * aVRMLModelsToBiu );
 
         fprintf( aOutputFile,
-                 "  children [\n    Inline {\n      url \"%s\"\n    } ]\n",
+                 "  children [\n    Inline {\n      url \"file://%s\"\n    } ]\n",
                  TO_UTF8( fname ) );
         fprintf( aOutputFile, "  }\n" );
     }
 }
 
 
-static void write_and_empty_triangle_bag( FILE* output_file, TriangleBag& triangles, int color )
+static void write_and_empty_triangle_bag( FILE* output_file, TriangleBag& triangles,
+                                          int color, double boardIU2WRML )
 {
     if( !triangles.empty() )
     {
-        write_triangle_bag( output_file, color, triangles );
+        write_triangle_bag( output_file, color, triangles, boardIU2WRML );
         triangles.clear( );
     }
 }
@@ -1290,8 +1293,6 @@
     // (aMMtoWRMLScale = 1.0 to export in mm)
     double boardIU2WRML = aMMtoWRMLunit / MM_PER_IU;
     fprintf( output_file, "Transform {\n" );
-    fprintf( output_file, "  scale %g %g %g\n",
-            boardIU2WRML , boardIU2WRML, boardIU2WRML );
 
     /* Define the translation to have the board centre to the 2D axis origin
      * more easy for rotations...
@@ -1324,25 +1325,28 @@
      * So the scaling factor from 0.1 inch to board units
      * is 0.1 / general_scaling_factor
      */
-    double wrml_3D_models_scaling_factor = 2.54 /  boardIU2WRML;
+    double wrml_3D_models_scaling_factor = 2.54 * aMMtoWRMLunit;
     // Export footprints
     for( MODULE* module = pcb->m_Modules; module != 0; module = module->Next() )
         export_vrml_module( pcb, module, output_file,
                             wrml_3D_models_scaling_factor,
-                            aExport3DFiles, a3D_Subdir );
+                            aExport3DFiles, a3D_Subdir,
+                            boardIU2WRML );
 
     /* Output the bagged triangles for each layer
      * Each layer will be a separate shape */
     for( int layer = 0; layer < LAYER_COUNT; layer++ )
         write_and_empty_triangle_bag( output_file,
                                       layer_triangles[layer],
-                                      pcb->GetLayerColor(layer) );
+                                      pcb->GetLayerColor(layer),
+                                      boardIU2WRML );
 
     // Same thing for the via layers
     for( int i = 0; i < 4; i++ )
         write_and_empty_triangle_bag( output_file,
                                       via_triangles[i],
-                                      pcb->GetVisibleElementColor( VIAS_VISIBLE + i ) );
+                                      pcb->GetVisibleElementColor( VIAS_VISIBLE + i ),
+                                      boardIU2WRML );
 
     // Close the outer 'transform' node
     fputs( "]\n}\n", output_file );