just thinking aloud - another way to manifoldness

Discussion in 'Software and Applications' started by primi, May 6, 2010.

  1. primi
    primi New Member
    I'm new to this thing. In fact, I only found this last week. And it is perfect for what I had in mind for a few weeks. Mind you, I have very very limited experience with 3d modeling. So what I am about to ask may be impossible, but here it is.

    I have used Poser a few years ago and with 3d printing it seemed like a perfect way to bring some character figures into our world. Poser is great because you get ready made characters that you can pose out of the box. But is a complete nightmare for making them manifold. I need a solution that would not require a lot of manual tweaking, which seems to be the only option that really works. Meshlab keeps crashing and Blender i hate. And if you need to repose your character it's all over again.

    I saw one tutorial for meshlab that makes just about anything manifold with a filter, but it makes a lot of polygons or a fat person. And it crashes. (might be my problem)

    How about using some morphing? I don't know anything about it, but Poser uses this for changing the way charaters look. So why not do something similar somehow and this is my question to you that have more experience and understand the technology.

    I would first pose the model in Poser and export it (.obj perhaps) and then import this in your favourite 3d application (I've briefly tryed Lightwave some time ago but it could be anything probably). Now you would make something like a bounding box or a very simple geometry with a lot of polygons. This structure would of course be manifold. Here comes the tricky bit. Is it now possible to morph this structure to look like your character and keep it manifold?? Morphing maybe only 99% or something. I like to think of it as having a hollow character and blowing a baloon inside that would take the shape of the character but of course still be a baloon (=manifold). Does this make sense at all?

  2. bartv
    bartv New Member
    What you're describing is called 'shrinkwrapping'.

    It has its own drawbacks though as the topology of most objects don't match that of a cube. Take a donut for example - there's no way you can morph a cube to a donut because of the shape in the center. As a result, a shrinkwrap operation often close holes in your model.

    Once again, there's no such thing as a free lunch, I'm afraid :)

  3. primi
    primi New Member
    I was afraid of such an answer. But I'm not droping this idea just yet. :D

    Even this new word (shrinkwrapping) returned some interesting results, like this one:


    This looks like what I had in mind. If I understand this correctly doing it like this would result in a manifold mesh, right? For more details on the resulting mesh you of course need more points on the wrapping one (pardon my terminology, still learning). Does anyone know if there is something similar possible in other 3d apps and what it is called?

  4. joris
    joris New Member
    Some applications such as Netfabb and Magics already repair models by shrinkwrapping them. Meshlab, an open source app that can help you repair models. also allows you to resurface the model.