topic Re: Polygon with variable number of sides in Libraries & objects

Polygon with variable number of sides

Anonymous — Wed, 28 Jan 2009 01:05:26 GMT

hello

is it possible to create a polygon with a variable number of sides ?

something like this ?

PGON nSide, 0, -1,
for i to nSide
i,
next i

where nSide is the variable for the number of side
and i, the numerotation of EDGE, incremented at each loop

i made it for VERT and EDGE, but impossible to realise with polygon

if anyone got the answer.....

Re: Polygon with variable number of sides

Barry Kelly — Wed, 28 Jan 2009 03:00:19 GMT

Jevrod wrote:
hello

is it possible to create a polygon with a variable number of sides ?

something like this ?

PGON nSide, 0, -1,
for i to nSide
i,
next i

where nSide is the variable for the number of side
and i, the numerotation of EDGE, incremented at each loop

i made it for VERT and EDGE, but impossible to realise with polygon

if anyone got the answer.....

You won't be able to put a for/next loop in a PGON command.
But if you only had a limited number of sides required you could say ...

IF nSide = 3 then
PGON 3, vect, status, edge1, edge2, ... edgen
ENDIF

IF nSide = 4 then
PGON 4, vect, status, edge1, edge2, ... edgen
ENDIF

IF nSide = 5 then
PGON 5, vect, status, edge1, edge2, ... edgen
ENDIF

.... etc.

Barry.

Re: Polygon with variable number of sides

Karl Ottenstein — Wed, 28 Jan 2009 05:12:12 GMT

If the computation of the points lends itself to iteration (presumably the reason you shows a for-loop), then I think that you can assemble the points into the parameter buffer in your loop by outputting them to the buffer with PUT and then use a GET (or USE) with the PGON to retrieve the computed values.

David Nicholson-Cole gives many examples of PUT/GET combinations in the GDL Cookbook. See:
http://archicad-talk.graphisoft.com/viewtopic.php?t=23839

Cheers,
Karl

Re: Polygon with variable number of sides

Anonymous — Wed, 28 Jan 2009 18:40:38 GMT

yeah, thanks for the PUT GET command, it's exactly what i need

Re: Polygon with variable number of sides

Anonymous — Wed, 28 Jan 2009 20:42:22 GMT

Of course, you can write pgons under this form

if bCond1 then
put 6, 0, 16, 1, 2, 3, 4, 5, 6 ! # 1
put 6, 0, 16, 7, 8, 9, 10, 11, 12 ! # 2
else
put 8, 0, 16, 1, 2, 3, 4, 5, 6, 7, 8 ! # 1
put 8, 0, 16, 9, 10, 11, 12, 13, 14, 15, 16 ! # 2
endif

for k = 1 to 2
pgon get(nsp/(3-k))
next k

But ... since you HAVE to declare each pgon, it is easier to write them directly.
I don't think put/get statements are of any help for pgons, in general.
It would be difficult to deal with buffer polycount.
Barry's solution seems more relevant.

if bCond1 then
pgon 6, 0, 16, 1, 2, 3, 4, 5, 6 ! # 1
pgon 6, 0, 16, 7, 8, 9, 10, 11, 12 ! # 2
else
pgon 8, 0, 16, 1, 2, 3, 4, 5, 6, 7, 8 ! # 1
pgon 8, 0, 16, 9, 10, 11, 12, 13, 14, 15, 16 ! # 2
endif

For a single planar pgon with a variable number of sides, put/get statements can work.
There are more simple ways to achieve this.
Use primitives only when not any current tool can achieve what you want.

Re: Polygon with variable number of sides

Anonymous — Sat, 07 Feb 2009 01:16:10 GMT

Karl wrote:
If the computation of the points lends itself to iteration (presumably the reason you shows a for-loop), then I think that you can assemble the points into the parameter buffer in your loop by outputting them to the buffer with PUT and then use a GET (or USE) with the PGON to retrieve the computed values.
Cheers,
Karl

I did that, using put get, worked for me. I was making coon object so the script was bit complicated, but, eventually got it assembled for up to 9x9 point coon, using two loops to calculate values and then 4 loops to assign them in proper order