how can i make an elliptical cone?

[Anonymous]

forgive me if this is obvious - these are my first steps in GDL and i've tried to work it out myself, but its actually something i'm doing for work so i'm trying not to waste too much time

basically i want to make an object like a cone but instead of having circles at either end, i need ellipses, and they have to be independently adjustable parametrically(!) How would i go about this?

This is for an object i am making that acts as the operator in a subtract SEO to give me a chamfered opening in a wall that i can then put windows into (I am trying to model a church building). See attached image for the cone version.

Cheers in advance

l>

[Frank Beister]

You can USE MULX, MULY or MULZ in front of the CONE command to get an elliptical cone.

For the openings it would be better to use WALLNICHE, which bases on CUTFORM. Unfortunatly there are no pictures on selfgdl to illustrate for non German speaking people, but there is a demonstration object on the CUTFORM page. The command works faster than SEOs and does not need additional elements in plan. The command has to be used inside the opening itself. To get an elliptical shape you have to use it in a way like this:

n=24
msk=15
sts=1+2+16+64+128
x=1.5 !width
y=2 !height
L=2 !length of the cone
distance=WALL_THICKNESS ! to the end

!calculation
r=x/2 !radius (not used) 
e=x/y !eccentricity (not used)
for i=0 to n
 w=i*360/n
 put x*cos(w)/2,b/2+y*sin(w)/2,msk
 next i

!cut
WALLNICHE n, 2, sts,   0,0,L  , distance, get(n*3)
WALLNICHE 5, 2, sts,   0,0,L  , distance,
  -a/2,0,msk,
   a/2,0,msk,
   a/2,b/2,msk,
  -a/2,b/2,msk,
  -a/2,0,msk

[Anonymous]

I have made an object that appears to make an opening
like what you show in your image.
It does not make an elliptical arch but a segmental arch
up to a half round arch. It is used to make a splayed opening
that an arch-head window is inserted into.
Is this what you are looking for ?
Please see attached image
Peter Devlin