Slicing animation

[EvilGnome]

For the slash at least you could use a combo of colour/displace/bump mapping with an alpha map reveal along the slash.

For the stabs you could use seperate models for before and after the blade makes contact, with the after model using further morphs for more damage.

Hope those helped?

[blaqDeaph]

Morph maps using Dragnet/Magnet and a small radius?

[Brent_3D]

The "Acid" plugin from worley.com (http://worley.com/polk/polk_acid.html), good animated burns, cuts in surface, and stains. Acid uses animatable procedural surfaces with bump channels driven by a null object. Hope this helps.

[Eclyps19]

Well I was also thinking of that Gnome but I can't seem to get a realistic looking cut going. I can't get the flesh to look like it's been sliced open.

[Eclyps19]

How would I make it so that I use a transparency map to create a slash at a certain frame? I've never used transparency maps before.

[Steve Warner]

I think Acid would be a great tool for this, but you could also probably do it with either Fi's Fake Boolean or the Shift Fake Boolean plugin. Here's a link to a mini-tutorial I did on it back in 2003.

http://forums.cgsociety.org/showthread.php?s=&threadid=76657

[Eclyps19]

Well what I was thinking of doing was making a Transparency UV map, where I can make the slices transparent... but I've never actually UVed a human before.

[modelo]

Hey Alec,
Are you talking about making a slice like a wound that is cut open?
How you go about it depends on the final look.

[Crocodilian]

has anyone given you a concept sketch? Or photo references?

I ask because "a stab wound" could mean many things. Most of the answers that discuss booleans are assuming that the stab wound changes the object geometry-- but that's usually not the case.

Unless something pulls apart a wound (say retractors in surgery), stab wounds generally stay closed.. .you have some blood on the surface, but that's a texture change, not a geometry change. Deep slices will pull apart on areas where there's muscle and tension --the abdomen and the shoulders as an example . . .

But unless you're in one of these situation where the geometry opens up, I would tend to do this entirely with textures. . .

[Eclyps19]

Well i'm doing this for some lawyers. The gave me the areas where the stabs were but no actual photos or anything. The main objective is to have the wounds visible for the jury to see. They need to say "Okay, he got stabbed there and there and there and I can tell because of those big gaping holes all over him"

The animation starts off with a body and a knife. The knife goes into the body, then the skin turns transparents, showing what was damaged. When the knife pulls out, the skin turns normal again but leaves a hole or a scar. Something simple, not complex. It does this 2 more times throughout the animation. I am trying to UV map the guy but it's a hell of a lot harder than it looks. Are there any ideas on how I can get this effect? I want to just use textures for now. Thanks

[toonafish]

something that could work:

-cut the object into 2 pieces along the edge where you want the cut to be
-make sure you have an overlapping row of polygons for both pieces so you can have the object cut into 2 pieces all teh time but don't see it because the end polygons have the same curvature as when they were stil one piece. You can hide them with a clipmap later on.
-create a weightmap you're going to use as a clipmap in Layout, so give the complete object a value of -100% and the overlapping row a value of 100%
-create an endomorph for both pieces where you move both edges along teh cut a bit away from eachother. Just as wide as you need the cut to be
-In layout give both pieces a weightmap gradient clipmap in the object properties panel
-create a Null you're going to use to animate the cut later on.
-add Normal Displacement to both pieces with a distance to object gradient and select the Null you just created. Give the gradient a sinsible distance depending on the size of your object.
-When you now move the Null towards the cut, the endomorph will kick in and it will look as if you actualy slice it with a onvisible knife.

-if you need so visualize the inside of the object you could copy the geometry you see behind the cut, flip the polys and give it a different surface name and make the surface 100% luminous and 0% diffuse. It will look like a boolean.

hope this helps, good luck

[Crocodilian]

. . .but why not use Poser? Forensic animations do not need to be cinema quality, and you can render in Lightwave, if you want better rendering.

Poser's got an endless supply of animations, textures and what not, and is frequently used for forensics, which are more or less a "pre-viz" sort of task.

For a forensic animation, I would expect the knife to go in, blood to appear, and that would be all-- no reason for a geometry deformation, unless chunks of flesh had been hacked off. . .which presumably didn't happen here. If they are referring to "big gaping holes" you ought to ask to see a photo of what they want.

You should ask the attorneys involved for guidelines regarding forensic renderings; different courts have different rules. You should also ask about clothing and age, race, sex of characters.

A forensic animation can be inadmissable based on inaccuracies in depiction-- the most important thing here is that you clarify with counsel EXACTLY what they want, preferably in writing.

[Eclyps19]

Okay, I spoke with the lawyers. This isn't going to court yet, it's just going to be used at a mediation between the 2 law firms and the family members to decide if they want to go to court. I did use poser for the model, and purchased it for that purpose, for humanoid figures. No clothes are needed and I cannot show any blood. The body stands still, there is no movement. Is there a way to texture slashes on in Poser? I am just learning the very basics of it at the moment.

[Crocodilian]

Is there a way to texture slashes on in Poser? I am just learning the very basics of it at the moment.

Sure. Take the texture map, and paint in some gore, save as "wounded". At the stab keyframe, you swap between the textures.

But wait, you say that "you can't show blood"? So what are you supposed to show? I guess just show the stabbing motion, and then perhaps leave a red "X" where the blade went in? Can be easily done in the texture techqnique noted above.

My guess is that they want a very matter of fact, non-prejudicial mockup. . .should be quickly accomplished in Poser.

[Eclyps19]

Sounds simple, yes, but its not. They want the skin to go transparent, show the mandible get chipped, then opaque, then the knife going under the rib cage at a certain angle, puncturing the heart at a certain place, pulling out a certain way, etc. These guys are picky!

Thanks for all your help though. They originally just wanted a hole in each wound chaped like () but it'd be too hard to see so I"m going to make it a red (). Thanks guys!

[Crocodilian]

OK, now you're supplying the details that are needed to make this work. I would expect them to be picky-- forensic simulations cannot misrepresent facts. As a parenthetical note, when working with a client, getting the specific requirements ("the brief") will leave you and they much happier in the end.

I highly recommend that you consult Zygote ( www.zygote.com ), the leading supplier of bio-medical anatomical models. . .very high quality stuff. See their biomed specialty page:

http://www.zygote.com/biomed_main.php

and their licensable models at:

http://www.3dscience.com/

[Eclyps19]

honestly, I thought the same thing as you, but they want it basic. Really Basic. They don't need all the flesh and brains and each bone and whatnot. I guess what they are trying to do is just show where the woulds were, rather than just telling. It's a strange case, yes. Thanks for your help though.

[HowardM]

You can do this using ClothFX and the sew tool, using Events to cut the flesh.
Its a pain in the ass at the moment to sew all the points (hope NT makes better tools for this) but if youre patient you can get some good flesh tearing....
:D

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