patch question

[Ravager]

what are patches? and how do you find the amount there is in a model?

[youngman]

Hi Ravager

 

what are patches? and how do you find the amount there is in a model?

 

Take a look at this link :- http://www.alienlogo.com/tincan/

Also take a look at page 127 in your TAoA:M manual & page 199 to 207 in the Technical reference book that came with A:M v14 (also on the cd).

 

To find out how many patches are in your model,in your modelling window right click and about half way down you will see 'info'.click on this to see the patch count or hairs for your model.

 

Hopes this helps

 

Jay

[Ravager]

thanks

[Fuchur]

From my Website:

 

Splines and Patches:

Splines are vectorial, non-linear curves. This curves are calculated by the computer. So it is not possible to create edges just 'close' curves. The splines can be manipulated by 'bias'-handlers and Control Points (CPs).

A:M works with Hash-splines, which have got some advantages to normal splines. Splines are not the geometry but only the borders of the 'patches' A patch contains of 2 splines and 4 Cps. But Hash-patches can be created from 3 CPs and even with 5 CPs although. Splines are trhough just a few controlpoints and very smooth forms good for characteranimation.

 

Informations of how many of them are there can be found in the modelingwindow if you click with the right mouse button into it and select "Info".

 

*Fuchur*

[phatso]

We should probably ask Martin why he chose the term "patch," but here's my take.

 

A patch is the surface defined by the 3, 4 or 5 control points around it, and the splines which join the CP's. In that sense it's like the polygons used by other programs, but Hash calls it by a different name because it has properties a polygon doesn't have.

 

A polygon is always flat - that is, it's a 2-dimensional plane. You "fake" curved surfaces by breaking them up into enough polygons that each individual polygon is too small to see. Since organic objects are almost always curved, what this means is that organic modelling with polygons is a wrong-headed approach at the most fundamental level, like using a screwdriver to pound nails.

 

Splines, on the other hand, can be curved - usually are - and this means the surfaces defined by intersecting splines can also be curved. A patch thus compares to a polygon as 3d compares to 2d or color compares to black-and-white. You don't have to define a surface using a gazillion polygons; you define the control points and splines, and the computer calculates the surface.

 

When you have multiple neighboring patches, the computer also calculates the patch-to-patch transitions, which are (ideally) smooth, as opposed to the case with neighboring polygons, which - since polygons are planes - cannot but show up as a sharp crease. Wireframes made up of 4-point patches are smoothest; 3-point and 5-point patches can involve ambiguous math.

 

Now, when you want to make inorganic, machine-based models, you can do it with patches. Simply peak the control points and make sure the splines that define a surface are in the same plane. In A:M, a polygon is simply a particular kind of patch, just as a 3d program can display a 2d image or a color monitor can display a black-and-white picture.