Figure 279. Joining Across Gaps

Select the line you want to join from (i.e. the new line will start from this line's end arrow) and type <Shift-J>. Then select the line you want to join to (i.e. the new line will end at this line's start cross) and type <Shift-J> again. A new line will be created, joining the first to the second (see Figure 279).

If, after having typed the first <Shift-J>, you want to abort, just make sure nothing is picked when you type <Shift-J> the second time.

If you ever plan to split slices where they have been joined across gaps, then use the process described below. If you don't, the split may not work. Slice lines have to intersect within quite tight tolerances for a split to work. This is not normally a problem when the slices are created through actual surface mesh, but can be if you are creating slices across air gaps.

Figure 280. Slice Across the Chest

Say, for example, you wanted to slice through a human chest (see Figure 280), but want to take the slices through the shoulder, joining with the other side, then split all these slices down the side of the chest and through the middle of the shoulder to create front and back sets of slices.

Figure 281. Draw Split Line Through Shoulder

The crucial part of this whole process is to use a straight (no curves allowed!) projection spline to create a split line to cut off the slices we don't want (see Figure 281). The same split line is used later, so don't delete it just yet.

Figure 282. Flat Hole in Chest Slices

Remove the bits that are split off, and you have a clean flat hole in the chest slices (see left side Figure 282). The hole is flat because all the slice ends are co-planer; the straight projected spline in effect creates a flat cutting plane. Use the method described above to join the slices across the gap (see right side Figure 282).

Figure 283. Create Front/Back Split Line

Now draw the line you want to use to split the slices into front and back groups (see left side Figure 283). Use the split line from above, the one used to split off the ends of all the chest slices at the arm/shoulder boundary, to trim off the unwanted bits of this second split line (see middle and right side Figure 283).

Figure 284. Co-planar Slices Across Gap

Next, join the second split line across the gap (see left side Figure 284). All of the slices created by joining across the gap will be co-planar, which means they can now be intersected and splitting will work (see right side Figure 284).

Figure 285. Slices Split Inside Shoulder

Figure 285 shows the final result; the original mesh, with slices cutting through the chest, split into front and back groups.