By Colin 'Chilli' Semple

Apologies for the obscene length of this tutorial but I wanted to produce one definitive tutorial that covers all the aspects of using ChilliSkinner.

Even if you are a veteran with ChilliSkinner, I still recommend that you take a look through this tutorial as it may well show a few things that you may not be aware of.  Indeed if you have some usage tips that I've missed then let me know.  :)

So here's the basic model. Nothing fancy, but it will suffice for demonstrating ChilliSkinner techniques that will be common to almost any model you want to skin.

If you would like to follow this tutorial in MAX I have made the model available on the downloads page.

Step 2

Click 'Auto Detach' to break your model into a number of polys.

Now there are two times when it's very useful to manually intervene when using ChilliSkinner, this is the first time; after 'Auto Detach' but before 'Clone'.  Actually you don't necessary have to use 'Auto Detach' at all if you prefer to detach the polys yourself.

Now we are going to manipulate the detached polys manually to give us more logical or 'un-foldable' groupings etc. Basically we will intervene to take control over what will eventually end up as our texture bitmap.

Step 3
Get familiar with tools that we'll be using...

We can use 'Hide Selected' and/or 'Hide Un-Selected' to hide polys and make it easier to work on the more difficult to reach polys.  Here I've hidden two wheels.

Use 'Toggle Visible' and 'Un-Hide All' to view/retrieve hidden objects.

We will also be using 'Attach Polys', 'Weld All' and 'Weld Selected'.  Note the different weld icons.

Step 4
I've hidden all the wheel components.  Now let's work on the body shell...  We are trying to group separate polys together so that  when flattened they will ultimately give us a sensible and understandable  bitmap to paint.  To do this we need to identify polys that if attached together would be able to be unfolded by ChilliSkinner.

We can see that the two sides of the truck will unfold fine.  But we can join them together by attaching them both to the roof of the truck.  

Select both sides of the truck and the truck's roof.

Step 5

Click 'Attach Polys', we now have one poly that consists of right side of truck, left side of truck and the roof itself.  However, although they are attached we still must weld them together to ensure that we don't have duplicate vertices at the joining edges.

Click 'Weld All'.  Now we have a contiguous mesh poly that can be unfolded.

Step6
Let's do a similar thing with the windscreen, bonnet and front grill.  Select them all.

Step 7

Click 'Attach Polys' and then 'Weld All'.  We now have a single poly where there were three and clearly it can be unfolded.

Step8
Let's do the same at the rear of the truck.  Select the rear windscreen, back of the truck and the tailgate.

Step 9

Click 'Attach Polys' and then 'Weld All'.  We now have another single poly where there were three and again it can be unfolded.

Step 10
Now here it gets interesting...  visualise the sides and roof unfolded i.e. purple poly group.  The roof will stay where it is and the two sides will swing up either side, pivoting at the top of the door windows where they join the roof.  It will give us a vaguely 'H' shaped poly when flat.  If your visual spatial reasoning is pretty good you could imagine that in the space behind the rectangular roof poly we would have space to lay out the beige tail section poly group...  (don't worry if this doesn't make any sense to you, just carry on and hopefully it'll become clear).

So let's attach the tail poly (beige) to the side/roof poly (purple).  Select both polys.

Click 'Attach'.

Click 'Weld Selected'.  Note: make sure you don't click 'Weld All' by mistake.

We can do an identical thing on the front poly i.e. the green one. as it would unfold to fit in the space in front of the roof rectangle.

Select both the front poly(green) and the sides/roof/tail polys (beige)

Click 'Attach'.

Select the verts along the front edge of the roof rectangle, this will be two from the sides/roof/tail and two from the front poly, you should have four vertices selected.  (shown in red).

Note: Often it's easier to select the correct verts in top/front/back/left/right viewports.

Click 'Weld Selected'.

If you haven't understood what we did or why we did it in the previous few steps hopefully this is where it'll become apparent.

We are now going to test out our spatial reasoning and indeed our vertex selection/welding skills by seeing if the poly will unfold or not.

We can see that the front and tail polys we attached have been folded along the edges where we selectively welded vertices.

ChilliSkinner has changed to colour of the poly to green to indicate that it unfolded without problems or distortion.

It's often useful to do this 'unfold test' as you complete each grouping of polys, the colour coding will also help to show you which ones you've done and which you haven't.

A quick aside here...  say I spot at this point that I don't really need those hexagonal polys at each end of the axles, after all they won't be seen because they are always covered by the wheels?  No problem, at this stage we can delete (or add) polys to our hearts content.

Back to the program...  select the lower rectangular poly (purple) and the polys either side of it, front and back in relation to the truck as shown.

Note: we can use 'Weld All' as opposed to 'Weld Selected' whenever it won't affect other vertices on the same poly other than the ones where we want the 'fold' to be.  In this case we want the 'fold' edges to be the edges front and back of the rectangular poly and these will be the only ones welded by 'Weld All'.  Use 'Weld All' when you can because it's easier and quicker.

Click 'Attach Polys'.

Again we select vertices along the edge where we want the fold to be.  In this case we will do both sides at the same time, you should have 8 vertices selected.

Click 'Weld Selected'.  Hide the object so we can work on the body underside.

Select the five polys as shown.

I 'froze' the body poly.  Sometimes it's useful to freeze rather than hide polys, you can't select them inadvertently but you can still see them which often makes it easier to orientate yourself to where you are working on the model.

Hopefully you are following what's going on, if so you'll realise that choosing the polys that are joined together is purely down to the user, there are always numerous ways to do it.

In this case I decided to select the polys around the axle.

Note: So far I haven't attached the end hexagons, the side and top rectangles.

Select the upward facing rectangular polys on the top of the hexagonal axle, then select the main axle component (attached in the previous step).