[Bf-committers] finding co-planer faces.

[Campbell Barton]

I might be wrong here but these formulas dont detect weather faces are 
on the same plane- IE Same faces could be offset but still facing the 
same way.

The method your talking about I have done- is my normal the same as your 
normal (within a given limit)

I was looking for a way of findinf objects that have the same normal and 
are level with each other. kinda tricky to explain. hope you get it.

A solution would be to say.

=is my normal the same as yours.
=If so then rotate my centre point by the objects normal (where Im 
currently stuck! how can I turn a normal into a rotation matrix???)
=having rotated the centre point of the face in question, is its X (or 
any other axis depending onm the rotation) the same as mine (what I mean 
by being on the same level.)
= if so themn its 'co-planer' and select it.

- Cam

Alexander Ewering wrote:

>
> On Sat, 24 Jul 2004, Campbell Barton wrote:
>
>> Alex, how did you detect co planer faces?
>> Id liek to know the formula.
>
>
> Uhm, the formula is
>
>     if (VecCompare(evl->n, evl2->n, 0.01)) {
>
> :)
>
> Basically, I just do that for every adjacent face until
> I don't find any face anymore that fulfills the
> if statement.
>
> The code is here, for your enjoyment:
>
> void select_coplanar_mesh(void)
> {
>     EditVlak *evl, *evl2;
>     int count= 1;
>
>     while (count) {
>         evl= G.edvl.first;
>         count= 0;
>         while(evl) {
>             if(vlakselectedAND(evl, 1)) {
>                 evl2= G.edvl.first;
>                 while(evl2) {
>                     if (ELEM4(evl2->v1, evl->v1, evl->v2, evl->v3, 
> evl->v4) ||
>                         ELEM4(evl2->v2, evl->v1, evl->v2, evl->v3, 
> evl->v4) ||
>                         ELEM4(evl2->v3, evl->v1, evl->v2, evl->v3, 
> evl->v4) ||
>                         ELEM4(evl2->v4, evl->v1, evl->v2, evl->v3, 
> evl->v4))
>                         if (VecCompare(evl->n, evl2->n, 0.01)) {
>                             if (!vlakselectedAND(evl2, 1)) {
>                                 count++;
>                                 evl2->v1->f |= 1;
>                                 evl2->v2->f |= 1;
>                                 evl2->v3->f |= 1;
>                                 evl2->v4->f |= 1;
>                             }
>                         }
>                     evl2= evl2->next;
>                 }
>             }
>             evl= evl->next;
>         }
>     }
> }
>
>
> | alexander ewering              instinctive mediaworks
> | ae[@]instinctive[.]de   http://www[.]instinctive[.]de
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>


-- 
Campbell J Barton

133 Hope Street
Geelong West, Victoria 3218 Australia

URL:    http://www.metavr.com
e-mail: cbarton@metavr.com
phone: AU (03) 5229 0241