
	Eg 2: Slicing a Hand

In previous versions of CySlice, cutting parallel sections was the best way of slicing up more organic shapes. This method has pretty much been superseded with the development of projected splines, and their use as paths for multiple rib sectioning (see Spline Projection). But, having said that, its still worthwhile going through the exercise of cutting up a mesh using parallel sections to demonstrate the use of chained slices.

Figure 322. Hand Mesh

In this example you will see how a hand is sliced. (Hand mesh courtesy of Cyber-Site Europe)

Stage 1: Preparing the Mesh

Again, you might want to reduce the number of polygons in the mesh to around 100K faces.

Stage 2: Cutting Slices

View the hand from the front, with an orthographic projection, and cut the parallel slices.

Figure 323. Parallel Slices

Push all the parallel slices to the Temp layer so they don't get in the way while you perform the next stage.

Stage 3: Drawing the Split Line

You can see from Figure 323 that the end arrows of adjacent slices don't line up. You can force them to line up by drawing a chained slice around the fingers and then using that to split the parallel slices.

View the hand from the side and start drawing a chained slice up the wrist and little finger.

Figure 324. Chained Slice Up Wrist

Zoom in to the little finger and continue the chain.

Figure 325. Chained Slice Up Little Finger

Hide everything except the little finger. Change your view to draw over the top of the finger.

Figure 326. Chained Slice Over Little Finger

Spin the finger around ready to draw down the inside. Because you are looking back at the links you have just drawn, up the outside of the little finger, there's a chance that when drawing you will accidentally pick one of these to snap to. You don't want this to happen, so you need to hide the existing links. Pick the entire chain, then unpick just the end link by dragging a box over the end arrow with the left mouse button. Then push the picked links to the Temp layer so they don't get in the way.

Figure 327. Hiding All But The Last Link

Now draw down the inside of the little finger.

Figure 328. Chained Slice Inside Little Finger

Continue drawing to the gap between the little and ring fingers. Zoom in to the gap between the fingers and slice across it.

Figure 329. Chained Slice Across Gap

Hide everything except the ring finger.

Figure 330. Chained Slice To Gap

Again, hide all links except the last one and continue drawing up the ring finger.

Figure 331. Chained Slice Up Ring Finger

Continue this process for each remaining finger and the thumb. Just push all the links in the Temp back on to the Work layer when you have finished.

Figure 332. Chained Slice Over Fingers and Thumb

You can see in Figure 332 that there's a break in the chain between the ring and middle fingers. Figure 333 shows a close up of the break.

Figure 333. Break in Chain

A break will occur when you have drawn a chained slice and some of the mesh faces are facing away from you. This is not a disaster; the break can be fixed. First, hide everything except the faces around the break, and zoom in for a closer look.

Figure 334. Faces Around Break

Change your view to make sure that the faces in the gap between the slices are facing you. Then join the two together by drawing a new link, snapping to the end of the first slice (the one with the arrow) and then to the start of the second slice.

Figure 335. Fixed Break

The split line is now complete.