What is Max’s equivalent to LightWave’s 1 point polygons?
Sorry for asking such a simple question, but the help system wasn’t very helpful.
Thanks. -Mike
Just imagine for a second we have no idea what “one-point polygons” are and we have no time to google them…
Could you educate us so we can answer your question?
I guess my assumption that LightWave terminology makes sense to everybody is a bad one.
Say I have a single postion vector (for example (1,1,1) ) and want to create “a point in space”. What is this type of geometry called in Max. A particle? A Vertice? Obviously it’s not called a one point polygon.
I’m converting a “center by volume” script I wrote in LScript to MAXScript, and need to create “these” to make it work.
Thanks for any help. -Mike
The problem is that Lightwave Modeler has a different geometry structure – it works with points, polygons and layers.
Max has object-oriented hierarchy, so the base level editable objects IS an object, where vertices, faces, polygons and edges can only be sub-object levels. In a way, a Max object can be seen as a Lightwave Layer, although it really isn’t.
Because of that, a vertex cannot exist without a base object to contain it. This means that you cannot create a simple point in space without creating an object first. Similarly, particles cannot be created outside of a host particle system.
It IS possible to have single vertices without corresponding polygons in a Max object (in Editable_Mesh or Editable_Poly). There is no such thing as a “one-point polygon” though, since by definition a face in a TriMesh ALWAYS has 3 points, and a polygon in a PolyMesh always has 3 or more. You can have a polygon using a single vertex 3 times, but it would be seen internally as “degenerated”.
Of course, you can create Nulls (which are called Dummy and Point Helpers) to store a position in space. But if you are scripting, you don’t really need to create scene objects just to calculate stuff, storing the data in simple Point3 values should be enough.
Btw, a Center Of Mass / Volume script is available in the MAXScript Reference (guess who put it there ;)). If that is what you are trying to do, of course…
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Bobo:
Hehe. Just saw your script. Mine uses a Monte Carlo integration method to figure the volume (the volume of the bounding box times the fraction of random points inside the bounding box that intersect the object). I still need to recode mine to show a game company. So you called yours Center of Mass / Volume? I originally named mine CG_Center, but “CG” was misleading. Good idea for a script though.
Thanks so much for letting me in on how Max works. I was going mad trying to find something on “points” in the docs. I’ll see if I can get Point3 values to work, or nulls, or it comes to it I can probably use tiny boxes in place of “particles”.
Be sure to let us know when your next dvd comes out!
Bao2: I don’t think helpers are what I need, but I bet they will come in handy for something else. Thanks.
-Mike
I think you are speaking of Point Helpers.
Go to max help and type “helpers” in the search tab. Then
you can see below it all the helpers: click on the “point” one.
You can use it for rotate things around it (objects, vertices,
faces, polygons) and for other uses like linking objects to it
so you moves the helper and all the objects linked move with
it. Read about all the helpers available in max help.
Bobo:
I forgot to ask, but your volume integration technique…it that a well known algorithm that provides an exact solution, or is it simply an approximation?
Thanks. -Mike
Mike, the method is not only well-known, it delivers EXACTLY the same results as the Measure Utility you can find in the Utilities tab of Max since version 1.0. Which leads me to the assumption the Measure utility uses the same algorithm.
It works well for closed volumes, even with internal “air pockets”. (For example if you have a sphere and another one attached to it with inverted normals, you will get the volume of the SOLID area between the two minus the central “hole”.
Bobo:
Your algorithm sounds like a better way (faster & more accurate) , but I’m almost done with mine so I’ll probably stick with it. I’m using tiny triangular polys instead of “points” BTW.
Thanks. -Mike