topic Re: Slab-like GDL or Param-O object for city planning? in GDL

Slab-like GDL or Param-O object for city planning?

Kaj_AL — Tue, 24 Sep 2024 08:30:47 GMT

Hi!

I'm working on a template for city planning and am currently looking for ways to easily mimic buildings in an early stage. Right now I'm using composite slabs with every story a different material, the materials being whatever functions the building has (residence, office, etc.). This doesn't feel optimal as the number of composites quickly become an unmanageable amount, and they're not quite as "smart" as I would like them to be.

So, my question is, is there anyway to build an object that behaves in a similar manner to a slab when it comes to modeling (new nodes with a click, easy to manipulate), or does any one have any other great ideas on how to do this?

Kind regards
Kaj

Re: Slab-like GDL or Param-O object for city planning?

Podolsky — Tue, 17 Aug 2021 07:19:18 GMT

You can mimic behaviour of slab in GDL object as close as possible with various hotspot tricks. It's not going to be the same, but can be something quite similar. Another option - to have accessory object, connected to polyline - in this case you can draw polyline and after just extract geometry into your GDL object (that will follow future changes of linked polyline).

In any case custom GDL object is very good solution. You just need to invest your time on writing GDL code - it depends on how good you with code writing and your creativity. In best scenario it can take two-three days of coding needed tool. But if you are slow and your programming skills are very limited - you can stack for month making this tool.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Tue, 17 Aug 2021 07:29:39 GMT

Hi!

Thanks for your quick answer!

The polyline option seems like a good solution, that probably will fit colleagues usede to 2D-drawing as well!

I am very new to GDL (I have browsed some old GDL cookbook and done a few exercises but that's it), but don't mind learning whilst using the composite slab workaround for now.

Do you know were I can find some references or examples on what needs to be done and how to do it?

Kind regards
Kaj

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Mon, 23 Aug 2021 14:41:46 GMT

Hi Kaj.AL,

Using the Accessories add-on is described here: https://helpcenter.graphisoft.com/knowledgebase/64527
The necessary library is in the Goodies package.

Select a subtype for your object from the add-on (eg. Model Element / Building Element / Covering / Accessory / Slab (Accessory)). Data will be set by the add-on in the parameters under gs_accessory_addon in the parameter list.
Read the code of "Plain Ceiling" or "Footing 2" to see how to use them.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Fri, 27 Aug 2021 06:46:54 GMT

Thanks Peter, I'll check it out and see if I can put the pieces together!

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Wed, 13 Oct 2021 11:46:07 GMT

Hi again!

I've slowly managed to put together a simple object that works as an add-on for slabs. Now I'm stumped on how to continue. What I would like to do is calculate stuff based on my object, and use these calculations in schedules or lists. For example I would like to calculate the area and volume, and from those values calculate an average number of apartments and so forth.

Do you have any suggestions on how to do this?

Link to object (made in Archicad 25): https://drive.google.com/file/d/1H1zIMQw84KaneYf5NkKRK1HkpV9ZGD5M/view?usp=sharing

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Erwin Edel — Wed, 13 Oct 2021 12:17:47 GMT

Probably too late to suggest now, but this does sound like something that the grasshopper connection would be perfectly suited to do. A.k.a. parametric design.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Wed, 13 Oct 2021 12:39:11 GMT

Hi!

It's never too late. I've been on the fence whether to get Grasshopper (or recommend the office to get it), but I've downloaded a trial now, so we'll se how it goes. Any clues on how to work it out in Grasshopper, or will it be self-explanatory once I start to get in to it?

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Erwin Edel — Wed, 13 Oct 2021 12:51:50 GMT

No, but your original case description sounded like it could use a paremetric approach and from what I've seen on youtube clips in the past, you can basically let grasshopper create Archicad 3D elements for you.

You might even be able to drive creation of existing buildings by combining GIS data and government vector data for site plans.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Thu, 14 Oct 2021 07:27:17 GMT

Thanks Erwin!

Especially the combining of GIS data and the local vector data with Grasshopper could cut our work time a lot! Will try it out when I get the chance!

However, for what I'm doing now I think a simple Archicad object should be enough, and working with Grasshopper might be to complicated for these types of early stages if it's to be implemented at the office.

So, I have two more open questions:

1. How do I use the Properties Script to get

a. The area of either my object or the slab upon which it is based?

b. The total volume of it?

I figure it's maybe using REQUEST or built-in properties, but I can't figure out how to use them properly?

2. How would you go about to create setbacks on this type of building object?

Thank you

/Kaj

Re: Slab-like GDL or Param-O object for city planning?

Erwin Edel — Thu, 14 Oct 2021 13:28:24 GMT

In case you are looking for some more information, here is a presentation from Enzyme https://geospatialworldforum.org/speaker/presentions2019/Connecting-GIS-BIM-Workflow-Case-Studies-Eugenio_Fontan.pdf

If you browse to slide 19 or so onwards you get a good introduction to how they use GIS data and grashopper to create 3D site models.

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Mon, 25 Oct 2021 08:05:07 GMT

With this approach the area has to be calculated by the script from the polygon coordinates. There is no existing GDL solution, the shoelace formula can be used if there are no curved edges.

Another approach could be making a label (if you don't need IES data or 3D geometry). Labels have access to slab data: http://gdl.graphisoft.com/reference-guide/column-beam-and-slab-parameters.

Properties can also be created using Property expressions without GDL.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Mon, 25 Oct 2021 09:56:06 GMT

Hi Peter! Thank you for your response.

I've set up the shoelace formula and it works fine. It feels as though it would be possible to calculate even with curved edges. The slab accessory seems to convert the arcs of the slab into a prism made up of straight polylines. I haven't really figured out where in the process this happens though.

If I look at the saved parameters, an accessory created from a rectangle slab has 15 parameters (x, y & status and the first point again with -1 as status). If I make one of the slab edges into an arc, the number of parameters reach around 150-300 instead (231 in my added screenshot). So, my thinking is that I could use those coordinates for the shoelace formula in some way to get a decently accurate result, would you say that's correct?

I haven't been able to "find" those coordinates in the Properties Script, only in the 3D. Is it possible to save them in the 3D script and let the properties script read them?

I also have not been able to control the appearance of the accessory when using an arc, neither RADIUS, TOLER nor RESOL seems to affect it. Do you know if this can be done?

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Wed, 27 Oct 2021 08:37:02 GMT

I looked into it and the add-on gives only straight edges to the slab object. It can't be controlled.

The polygon is a parameter, it should be available in the properties script. There is an example in the "Footing 1" object.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Tue, 02 Nov 2021 16:03:12 GMT

Thank you Peter!

I looked into the Footing object and could figure out what to use in my object. It's not the most elegant, but it does the job.

The next step would be to figure out

1. How to do setbacks within the same object.

2. Connect a label that can show custom properties

Is that anything you could point me towards?

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Mon, 08 Nov 2021 12:13:25 GMT

Sorry, labels can't show properties from the properties script, those are only available for Lists (not Interactive Schedules). But you can access parameters from a label (use REQUEST "assoclp_parvalue") and do the calculations in the label.

Setbacks like solid operations? That sounds difficult, you'd have to intrepret the shape somehow to know what to do.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Tue, 09 Nov 2021 08:11:46 GMT

Thank you Peter!

Labels: Okay, I've started looking into the "assoclp_parvalue", but I'm a bit lost. Sorry if my questions are a bit basic, but so am I.

An example: In my object, I have a parameter called num_stories which is an integer dictating the number of stories. How would I write the REQUEST to use this parameter in the label?

Setbacks: Yes, either that, or perhaps a separate PRISM with editable hotspots (but preferably something a bit simpler).

Is it possible to somehow ask for another slab or polyline? Say that I want to have a 2 meter setback on my top story. Can I within my object create a button which, when clicked, prompts the user to select an additional slab/polyline, and from this shape subtract the 2 meter setback?

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Fri, 12 Nov 2021 15:24:51 GMT

num_stories = 0 ! this will receive the value if found n = REQUEST ("ASSOCLP_PARVALUE", "num_stories", _unused, type, flags, dim1, dim2, num_stories)

type, flags, dim1, dim2 are returned from the labeled object, you can double-check them to see whether it's the same parameter that you expect.

There is no polygon input method in GDL. You could draw a set of editable hotspots on the polygon to define a second polygon that can be edited vertex by vertex, and you might need some button on the UI to reset it to the current contour of the object.

Re: Slab-like GDL or Param-O object for city planning?

Kaj_AL — Fri, 19 Nov 2021 13:33:08 GMT

Thanks! I got it to work with the more simple parameters!

However, I can't seem to get it to work with the array of coordinates that is my starting polygon. How would I request that array?

Another question that popped up; can I in the user interface have a text box for typing in something that goes straight to an array parameter? So, array[1] has it's own box, as does array[2] and so on.

Kind regards

Kaj

Re: Slab-like GDL or Param-O object for city planning?

Peter Baksa — Mon, 22 Nov 2021 10:49:44 GMT

The request always returns a one-dimensional array:

p_values: for ASSOCLP_PARVALUE returns the parameter value or array of values. The array elements are returned successively, row by row as a one dimensional array, independently of the dimensions of the variable specified to store it. If the variable is not a dynamic array, there are as many elements stored as there is room for (for a simple variable only one, the first element). If values is a two dimensional dynamic array, all elements are stored in the first row.

You need to convert the one-dimensional array to two-dimensional (or use it as such, calculating indices).

Most UI_...{2} commands can show individual array elements. The reference guide always states where they can be used.