I am working with Vickie 4. Ideally I am trying to use her in a scene as an alien. In the scene I am making I am trying to open her mouth very, very wide--large enough to swallow another human whole. She is planned to be a pretty evil alien, except I have no idea how to make her mouth open to that extent. I'm not even sure if its possible. I'd imagine with deformers or something, turning limits off, but not sure if its workable.

Any advice? 

you can start by using all the available mouth open , smile, etc morphs and see how that goes. Then you need to use magnets or the morph brush.

You might be able to frankenstein V4 and another character with a huge mouth by compositing in a paint program, with some postwork to clean it up. 

Having worked something along those lines, the other problem you will run into after stretching her mouth so much, is the stretching of her skin, both the mesh and the texture. Not only will her mouth distort, but all her lower jaw and tongue. It will not look real, blocky in appearance unless you subdivide it and come up with new textures where it does stretch. 

 I am working with Vickie 4. Ideally I am trying to use her in a scene as an alien. In the scene I am making I am trying to open her mouth very, very wide--large enough to swallow another human whole. She is planned to be a pretty evil alien, except I have no idea how to make her mouth open to that extent. I'm not even sure if its possible. I'd imagine with deformers or something, turning limits off, but not sure if its workable.

 

Any advice? 

Remember that her mouth open morphs are just that - Morphs. We naturally want to treat those as being rigged, but they're just morphs and they'll deform pretty horribly if you try to exceed the limits. (Note: The Lower Jaw is rigged, sorry. But, I think it works in close association with JCM's in open/close. I don't think it has deformers, itself. It just provides a base for the tongue rigging and an anchor for the separate Lower Jaw group.)

The easiest way would be to use magnets and the Morph Tool to smooth up the edges. Don't forget to include the Lower Jaw group and all the Tongue groups, as well, when selecting groups to be deformed by your magnets. (The tongue is rigged. Go figure.... Gee, why did they do that? :) ) In later versions of Poser, the Morph Tool spans groups, so using it is a lot easier than it used to be. (Not sure when they incorporated that feature.)

Texture stretching will happen. But, it probably won't be too much of an issue, since you're already going to morph her mouth into something that's probably pretty grotesque to begin with.

Unless you're stretching this to ludicrous levels, you probably won't need to make a custom morph in an external 3D application. Poser's Morph Tool should be enough to smooth it up nicely.

PS - Don't forget about the Neck group in your deformation. V4's neck will probably need to follow the deformation closely, as well, if it's very severe.

The closest I can find is Shrieker over at RDNA.  The mounth opens wide enough for a good size bird model but I don't think you'll get a morph big enough for full size human model. 

The product is still on sale but today is likely the last day.