topic Re: Slab Accessory Question in Libraries & objects

Slab Accessory Question

James Murray — Tue, 22 Apr 2008 19:57:57 GMT

It seems that wall accessories can draw true arcs, while slab accessories cannot. I don't see anything in the polygon data from the slab that indicates a curve, and the default slab accessory objects use a chain of LINE2s to approximate arcs. If you use a dashed line type the results are not great.

Can anyone add to my limited knowledge?

TIA,

Re: Slab Accessory Question

LiHigh — Wed, 23 Apr 2008 01:15:59 GMT

Yes, you are right!

Re: Slab Accessory Question

Thomas Holm — Wed, 23 Apr 2008 04:13:42 GMT

James wrote:
It seems that wall accessories can draw true arcs, while slab accessories cannot...

Roofs can't either, can they?

Re: Slab Accessory Question

Anonymous — Wed, 23 Apr 2008 08:30:21 GMT

Thomas wrote:
Roofs can't either, can they?

No, they can't. Only wall accessory produces true 2D arcs.
On other hand, 3D doesn't follow wall geometry (curved walls), so nothing is perfect.

@James.
I am afraid you will have to adapt wall accessory 2D data to slab accessory, to achieve this. Good luck, and a lot of patience.

@Howard.
May be you already did it? I remember a nice slab accessory you wrote.

Cheers,
Olivier

Re: Slab Accessory Question

James Murray — Wed, 23 Apr 2008 11:58:16 GMT

Olivier wrote:
I am afraid you will have to adapt wall accessory 2D data to slab accessory, to achieve this. Good luck, and a lot of patience.

Well, the wall accessories directly ask the walls if they are curved, since there's a subtype parameter for that. On the slab, you would have to analyze a series of points to see if it might represent a curve. It would hurt my head and it wouldn't be very robust IMO.

Why can't that ac_coords data be in x, y, s format, like it would be if you saved the slab as an object? Instead it's this weird hack to say where the polygons end, and no other status codes in sight.

Re: Slab Accessory Question

Thomas Holm — Wed, 23 Apr 2008 13:35:10 GMT

James wrote:
Why can't that ac_coords data be in x, y, s format, like it would be if you saved the slab as an object? Instead it's this weird hack to say where the polygons end, and no other status codes in sight.

Guess we'll need a new 3D engine before we get that. But put it on the wish list!

Re: Slab Accessory Question

Anonymous — Wed, 23 Apr 2008 14:03:08 GMT

James wrote:
Well, the wall accessories directly ask the walls if they are curved, since there's a subtype parameter for that. On the slab, you would have to analyze a series of points to see if it might represent a curve. It would hurt my head and it wouldn't be very robust IMO.

You are right. We lack a subtype parameter for curved slabs/roofs.
So it seems difficult/impossible to achieve this. May be the reason why GS did not implement this feature.

And yes, struggling with these ac_coords and ac_whole_poly params is a pain.

Re: Slab Accessory Question

LiHigh — Wed, 23 Apr 2008 16:45:34 GMT

Olivier wrote:
@Howard.
May be you already did it? I remember a nice slab accessory you wrote.

It's approximation!

@Jame,
There is a way to determine if the segment is curve. However it's very complicated.
I would like to help. Let me know what's that you are trying to do.