Sword Stabbing

[Blade_Rain]

I want to make an animation of a sword/knife penetrating a watermelon, or body. I know I'd most likely have to use masks.

How would I animate a sword penetration? Please tell me if there are other ways than using masks. I'd always assumed "make one half of the body on one layer, the other half on another, and keep them close." or something along those lines.

-Ken

[synthsin75]

That would work. You'd just need your sword layer between the to half layers. But this will only work if you're viewing you 'stabbed' object from the right angle (about 3/4). Also this becomes overly complicated to separate the halfs of a fully rigged character.

But masking is your easiest solution.
Try this: Make a filled shape for an object. Make a filled shape that will be used to 'hide' the penetrating blade (so a bit wider than the blade and long enough to cover the depth of the 'stab'). Put these in a group or bone layer with your blade layer. Order them, from top to bottom, blade, hide shape, stabbed object.
Now here's the masking bit. In the masking tab of your group/bone layer, set it to reveal all. Set your hide shape layer to 'subtract from mask'. Stab away..

What this does: Reveal all just tells it you want to see everything in the group that is set to 'mask this layer' (default). 'Subtract from mask' means that you want to remove this area (the shape on that layer) from view. The only real tricky part is to remember that this only removes from this layer up.

Here's a simple example.

In this example, if you move the 'mask' layer to the bottom of the group you'll see that it now removes both the body and the blade from view.

Hope that helps.

[Rasheed]

You mean something like this?



One layer above with the partial shape and the cut, one layer below with the entire shape (without the cut). The blood is between the sword layer and the lower melon layer.

File: melon_sword.zip

[heyvern]

Don't be afraid of masking. It is very powerful and a big time saver.

Having said that... if you really really have some kind of phobia of masking due to a childhood incident you could have a "collapsible" sword or knife. If the knife is very straight just add extra points and animate the endpoints moving towards the hilt If the action is fast enough you could just animate the whole blade shape moving into the handle.

Does this make sense? i would use the mask though... less key frames and a lot easier.

-vern

[Blade_Rain]

Thats exactly what I'm talking about. Gracias all!

[Blade_Rain]

Just tried it... It worked surprisingly well. Masking is my new friend!

[Blade_Rain]

Okay, now that I've got that down, howzabout slicing something in half, in 3/4 view?

[synthsin75]

Rasheed's example may be easiest for slicing something in half, unless you're wanting to slice, say.....umm...., a complicated rigged character. Who knows, someone's bound to get that gruesome.

That would be much more complicated. First you'd need to duplicate your character. You'd need to define where you're planning to slice, and then mask out (subtract) opposite halves of each duplicate. Plus add in any innerds you may want.

This would allow you to freely animate each half as it falls apart. Like I said, gruesome.

[Rasheed]

Like I said, gruesome.

BTW, whoever said animation has to be family-friendly? Swords are made to kill people... or slice melons as an act of terror. It is a weapon of war.

[slowtiger]

Slicing a character can be much easier. Remember: the actual cut will take place in only one or three frames.

It is possible to use the standard rigged character before the cut, then switch to a modified (= wounded or separated) character after the cut. And the actual cutting could be done with a bitmap of the last frame of character #1. Add gore (= blood) and you're done.

[Blade_Rain]

Thanks again!

I freakin' love this forum.