topic Re: Curved Segment using GDL Primitive Elements in GDL

Curved Segment using GDL Primitive Elements

Nader Belal — Mon, 27 Dec 2021 13:00:53 GMT

Hi everyone,

Can someone explain me how to create curved arcs and surfaces using VERT, VERT{2}, TEVE, EDGE, & PGON ??

I tried searching for an example to follow, but I couldn't find any.

Re: Curved Segment using GDL Primitive Elements

runxel — Mon, 27 Dec 2021 21:27:32 GMT

I don't think that is possible.

How do you got the idea it could be done? With those commands you basically model single polygons. And polygons can never be bend...

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Mon, 27 Dec 2021 22:00:22 GMT

Well I just have found out how ... you can, but it a time consuming process

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Mon, 27 Dec 2021 22:00:57 GMT

Just give me a shout for tomorrow or after tomorrow and I will give you the steps to do it

Re: Curved Segment using GDL Primitive Elements

SenecaDesignLLC — Tue, 28 Dec 2021 15:16:17 GMT

Curious as to why you would want to use the primitives?

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Tue, 28 Dec 2021 16:29:30 GMT

Because sometimes, and depending of the elements' complexity/resource usage, it can be more cost effective to just model the desired element using Primitives.

In my actual case, since GDL lacks morphing or mapping (don't know the correct term) a regular cubic model to a similar curvilinear shape, and scripting that will be more be more time consuming with lower quality result.

That besides, the god damned standard GDL manual doesn't have an example for that.

Re: Curved Segment using GDL Primitive Elements

SenecaDesignLLC — Tue, 28 Dec 2021 20:05:59 GMT

Curious, what are you modeling?

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Tue, 28 Dec 2021 21:43:22 GMT

Curved cabinet door panel

Re: Curved Segment using GDL Primitive Elements

SenecaDesignLLC — Tue, 28 Dec 2021 22:38:39 GMT

I just use tubes and map the surface around the segments I guess I felt like primitives would be more work.

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Wed, 29 Dec 2021 02:06:37 GMT

Usually I would do that, but the overhead is unacceptable

Re: Curved Segment using GDL Primitive Elements

runxel — Wed, 29 Dec 2021 18:53:46 GMT

Okay, great, always love to discover new methods!

I'm really eager to know how you achieve this.

Re: Curved Segment using GDL Primitive Elements

leceta — Wed, 29 Dec 2021 21:00:51 GMT

same here, I still need to see this with my eyes. A simple example should be enough to show the implementation... How are you defining curves using vertices, edges and polygons (and apparently not being able to use status codes on corresponding commands)? Very curious...

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Wed, 29 Dec 2021 21:32:33 GMT

Alright, I will make two posts and share it here

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Wed, 29 Dec 2021 21:35:01 GMT

Buy the way, I'm half way through

Re: Curved Segment using GDL Primitive Elements

Nader Belal — Wed, 29 Dec 2021 21:35:49 GMT

By the way, I´m half way through

Re: Curved Segment using GDL Primitive Elements

Peter Baksa — Wed, 05 Jan 2022 15:42:12 GMT

All GDL commands will get translated to these primitives by AC. Curved surfaces just have many small polygons.

Here is some help for using TEVE: http://gdl.graphisoft.com/gdl-style-guide/script-type-dependent-recommendations

I'd recommend using BPRISM_ and COOR{3} for a curved panel btw.

Re: Curved Segment using GDL Primitive Elements

leceta — Wed, 05 Jan 2022 23:42:24 GMT

Thanks Peter, I understand this, its like many other platforms, rhino for example, where one can define nurbs surfaces (mathematically continuous) but still are represented (and only represented) as meshes (discrete representations). Further operations on that surface still are on the nurbs, though.
My surprise was in relation to the aim of defining "curves" or "curved surfaces" through a discrete system, which "is" (or "seems", afaik) an oxymoron.
In a private conversation, if I understood him correctly, Nader was trying to obtain a smooth representation of a discrete surface, which is all about shaders (well, and in the case of GDL applying the appropriate status code to de edges/polygons.

Re: Curved Segment using GDL Primitive Elements

SenecaDesignLLC — Wed, 05 Jan 2022 23:55:30 GMT

My poly tube calculates the positioning of the materials along curve sections for this exact purpose in terms of like a wood curved railing so that you can get a consistent wood grain all the way up the curve One of the things I hate about ArchiCADs railing tool

Re: Curved Segment using GDL Primitive Elements

SenecaDesignLLC — Wed, 05 Jan 2022 23:59:14 GMT

https://youtu.be/3WW5X7Q8FIc

Re: Curved Segment using GDL Primitive Elements

leceta — Mon, 10 Jan 2022 18:46:15 GMT

thank for the video seneca, really great job!
But for the sake of clarity in relation to the post, let me comment that your particular example is more related to texture UV mapping (TEVE, I suppose) than shading (which happens to be related to vertex normals). Correct me if I'm wrong.

bests, Aitor