source/createMesh.py

@@ -705,6 +705,7 @@ def Create_Pan_Head(HOLE_DIA, HEAD_DIA, SHANK_DIA, HEIGHT, RAD1, RAD2, FACE_OFFS
 
     verts.append([SHANK_RADIUS, 0.0, (0.0 - HEIGHT)])
     Row += 1
+    washer_face_z = Start_Height - HEIGHT
 
     verts.append([SHANK_RADIUS, 0.0, (0.0 - HEIGHT) - Start_Height])
     Row += 1
@@ -716,7 +717,7 @@ def Create_Pan_Head(HOLE_DIA, HEAD_DIA, SHANK_DIA, HEIGHT, RAD1, RAD2, FACE_OFFS
 
     # Global_Head_Height = HEIGHT  # UNUSED
 
-    return Move_Verts_Up_Z(sVerts, Start_Height), faces, HEIGHT
+    return Move_Verts_Up_Z(sVerts, Start_Height), faces, HEIGHT, washer_face_z
 
 
 def Create_Dome_Head(HOLE_DIA, HEAD_DIA, SHANK_DIA, HEIGHT, RAD1, RAD2, FACE_OFFSET, DIV_COUNT):
@@ -843,6 +844,8 @@ def Create_Cap_Head(HOLE_DIA, HEAD_DIA, SHANK_DIA, HEIGHT, RAD1, RAD2, DIV_COUNT
     verts.append([HEAD_RADIUS - BEVEL, 0.0, 0.0 - HEIGHT])
     Row += 1
 
+    washer_face_z = -HEIGHT
+
     # rad2
     for i in range(0, 100, 10):
         x = sin(radians(i)) * RAD2
@@ -855,7 +858,7 @@ def Create_Cap_Head(HOLE_DIA, HEAD_DIA, SHANK_DIA, HEIGHT, RAD1, RAD2, DIV_COUNT
 
     faces.extend(Build_Face_List_Quads(FaceStart, Row - 1, DIV_COUNT))
 
-    return sVerts, faces, HEIGHT + RAD2
+    return sVerts, faces, HEIGHT + RAD2, washer_face_z
 
 
 def Create_Hex_Head(FLAT, HOLE_DIA, SHANK_DIA, HEIGHT):
@@ -868,6 +871,7 @@ def Create_Hex_Head(FLAT, HOLE_DIA, SHANK_DIA, HEIGHT):
     Undercut_Height = (Half_Flat * (0.05 / 8))
     Shank_Bevel = (Half_Flat * (0.05 / 8))
     Flat_Height = HEIGHT - Undercut_Height - Shank_Bevel
+    washer_face_z = -HEIGHT + Undercut_Height
     # Undercut_Height = 5
     SHANK_RADIUS = SHANK_DIA / 2
     Row = 0
@@ -927,7 +931,6 @@ def Create_Hex_Head(FLAT, HOLE_DIA, SHANK_DIA, HEIGHT):
 
     x = tan(radians(60 / 3)) * Half_Flat
     dvec = vec3 - Vector([x, Half_Flat, 0.0])
-    Lowest_Point = -dvec.length
     verts.append([x, Half_Flat, -dvec.length])
 
     x = tan(radians(60 / 2)) * Half_Flat
@@ -1061,7 +1064,7 @@ def Create_Hex_Head(FLAT, HOLE_DIA, SHANK_DIA, HEIGHT):
 
     Spin_Verts, Spin_Faces = SpinDup(verts, faces, 360, 6, 'z')
 
-    return Spin_Verts, Spin_Faces, 0 - (-HEIGHT)
+    return Spin_Verts, Spin_Faces, 0 - (-HEIGHT), washer_face_z
 
 
 def Create_12_Point(FLAT, HOLE_DIA, SHANK_DIA, HEIGHT, FLANGE_DIA):
@@ -1600,9 +1603,10 @@ def Create_Thread_Verts(INNER_DIA, OUTTER_DIA, PITCH, HEIGHT,
     Deg_Step = 360.0 / float(DIV_COUNT)
     Height_Step = float(PITCH) / float(DIV_COUNT)
 
-    NUM_OF_START_THREADS = 4.0
+    NUM_OF_START_THREADS = 2.0      # Was 4 in the very first submission
     NUM_OF_END_THREADS = 3.0
     Num = int((HEIGHT - ((NUM_OF_START_THREADS * PITCH) + (NUM_OF_END_THREADS * PITCH))) / PITCH)
+    # This uses less than the requested bolt length by up to 1 pitch, after 5 revolutions
     Row = 0
 
     Crest_Height = float(PITCH) * float(CREST_PERCENT) / float(100)
@@ -1774,15 +1778,20 @@ def Create_External_Thread(SHANK_DIA, SHANK_LENGTH, INNER_DIA, OUTTER_DIA,
     )
     Total_Row += Thread_End_Row
 
+    # Make a final correction for the bolt length to mitigate rounding errors during manufacture
+    Mini_adder = Lowest_Z_Vert + SHANK_LENGTH + LENGTH
+    if Mini_adder < LENGTH * 0.01:
+        Mini_adder = 0  # Catches a very thin shim and also negative situations, worst case error is 1%
+
     verts.extend(Shank_Verts)
-    verts.extend(Thread_Start_Verts)
+    verts.extend(Move_Verts_Up_Z(Thread_Start_Verts, -Mini_adder))    # Needs moving down by the mini_adder
-    verts.extend(Thread_Verts)
+    verts.extend(Move_Verts_Up_Z(Thread_Verts, -Mini_adder))          # so that any missing length is added
-    verts.extend(Thread_End_Verts)
+    verts.extend(Move_Verts_Up_Z(Thread_End_Verts, -Mini_adder))      # between the thread and the shank.
 
     faces.extend(Build_Face_List_Quads(Face_Start, DIV_COUNT, Total_Row - 1, 0))
     faces.extend(Fill_Ring_Face(len(verts) - DIV_COUNT, DIV_COUNT, 1))
 
-    return verts, faces, 0.0 - Lowest_Z_Vert
+    return verts, faces, 0.0 - Lowest_Z_Vert + Mini_adder
 
 
 # ####################################################################
@@ -2379,13 +2388,16 @@ def Bolt_Mesh(props, context):
             props.bf_Philips_Bit_Dia / GLOBAL_SCALE * (0.5 / 1.82),
             props.bf_Phillips_Bit_Depth / GLOBAL_SCALE
         )
+
     # Head Mesh
+    # Define the washer face of the bolt, i.e. the underside. Some bolts have a bevel or radius to the shank included
+    # Their head height causes an incorrect shank/thread length determination.
+    washer_face_z = 0         # z-axis height, some Heads return a variable that overwrites this
     if props.bf_Head_Type == 'bf_Head_Hex':
-        Head_Verts, Head_Faces, Head_Height = Create_Hex_Head(
+        Head_Verts, Head_Faces, Head_Height, washer_face_z = Create_Hex_Head(
             props.bf_Hex_Head_Flat_Distance / GLOBAL_SCALE, Bit_Dia,
             props.bf_Shank_Dia / GLOBAL_SCALE, props.bf_Hex_Head_Height / GLOBAL_SCALE
         )
-
     elif props.bf_Head_Type == 'bf_Head_12Pnt':
         Head_Verts, Head_Faces, Head_Height = Create_12_Point_Head(
             props.bf_12_Point_Head_Flat_Distance / GLOBAL_SCALE, Bit_Dia,
@@ -2394,7 +2406,7 @@ def Bolt_Mesh(props, context):
             max(props.bf_12_Point_Head_Flange_Dia / GLOBAL_SCALE, props.bf_12_Point_Head_Flat_Distance / GLOBAL_SCALE)
         )
     elif props.bf_Head_Type == 'bf_Head_Cap':
-        Head_Verts, Head_Faces, Head_Height = Create_Cap_Head(
+        Head_Verts, Head_Faces, Head_Height, washer_face_z = Create_Cap_Head(
             Bit_Dia, props.bf_Cap_Head_Dia / GLOBAL_SCALE,
             props.bf_Shank_Dia / GLOBAL_SCALE, props.bf_Cap_Head_Height / GLOBAL_SCALE,
             props.bf_Cap_Head_Dia / GLOBAL_SCALE * (1.0 / 19.0),
@@ -2407,9 +2419,8 @@ def Bolt_Mesh(props, context):
             props.bf_Shank_Dia / GLOBAL_SCALE, props.bf_Hex_Head_Height / GLOBAL_SCALE,
             1, 1, 0, props.bf_Div_Count
         )
-
     elif props.bf_Head_Type == 'bf_Head_Pan':
-        Head_Verts, Head_Faces, Head_Height = Create_Pan_Head(
+        Head_Verts, Head_Faces, Head_Height, washer_face_z = Create_Pan_Head(
             Bit_Dia, props.bf_Pan_Head_Dia / GLOBAL_SCALE,
             props.bf_Shank_Dia / GLOBAL_SCALE,
             props.bf_Hex_Head_Height / GLOBAL_SCALE, 1, 1, 0,
@@ -2431,11 +2442,24 @@ def Bolt_Mesh(props, context):
     verts.extend(Move_Verts_Up_Z(Head_Verts, Head_Height))
     faces.extend(Copy_Faces(Head_Faces, Face_Start))
 
+    make_shank = (props.bf_Shank_Length / GLOBAL_SCALE)
+    make_thread = (props.bf_Thread_Length / GLOBAL_SCALE)
+    if washer_face_z != 0:
+        # At this point the mesh is back at z=zero. The washer face may be randomly above this depending on
+        # the head choice. Optional returned variable is used to shorten up the shank/thread.
+        # If the Head function modified the washer_face-z we are here to make a length correction.
+        washer_face = washer_face_z + Head_Height
+        make_shank = (props.bf_Shank_Length / GLOBAL_SCALE) - washer_face
+        if make_shank < 0:
+            # If all the shank length is used up then take it off the thread length
+            make_thread = (props.bf_Thread_Length / GLOBAL_SCALE) + make_shank
+            make_shank = 0
+
     Face_Start = len(verts)
     Thread_Verts, Thread_Faces, Thread_Height = Create_External_Thread(
-        props.bf_Shank_Dia / GLOBAL_SCALE, props.bf_Shank_Length / GLOBAL_SCALE,
+        props.bf_Shank_Dia / GLOBAL_SCALE, make_shank,
         props.bf_Minor_Dia / GLOBAL_SCALE, props.bf_Major_Dia / GLOBAL_SCALE,
-        props.bf_Pitch / GLOBAL_SCALE, props.bf_Thread_Length / GLOBAL_SCALE,
+        props.bf_Pitch / GLOBAL_SCALE, make_thread,
         props.bf_Crest_Percent,
         props.bf_Root_Percent, props.bf_Div_Count
     )