topic Re: Request the top area of this slab? in GDL

Request the top area of this slab?

yongler — Thu, 31 Oct 2024 02:39:53 GMT

I want to make GDL for floor slab accessories and request the top area of this slab. I wrote this: n = REQUEST("SLAB_TOP_SURF" , " " , _area ) But it was not successful. May I ask how to write this sentence?

Re: Request the top area of this slab?

Pertti Paasky — Thu, 31 Oct 2024 07:03:12 GMT

I think the object does not get the area information of the slab, but You can calculate the area from the point information.

https://www.wikihow.com/Calculate-the-Area-of-a-Polygon this site tells how.

Re: Request the top area of this slab?

Barry Kelly — Thu, 31 Oct 2024 07:32:36 GMT

@Pertti Paasky wrote:

I think the object does not get the area information of the slab

This is correct.

@yongler

SLAB_TOP_SURF is not for use in REQUEST commands.

It is a Global Variable that can be used only in lists or labels - i.e. a label can give you the area of a slab.

As Pertti suggests, you will have to calculate the area from the point information (nodes) of the slab.

I am not quite sure why you would want the area for an accessory object though?

Barry.

Re: Request the top area of this slab?

yongler — Fri, 01 Nov 2024 01:33:01 GMT

Thank you very much！ This is exactly what I want.

!!!===求板面积，不包括挖洞的======= data1 = 0.0 data2 = 0.0 FOR i = 1 to points -1 !!!叉乘 data1 = P[i][1] * P[i+1][2] + data1 data2 = P[i+1][1]* P[i][2] + data2 next i slab_area = (data1 - data2 ) /2 !!!单层面积

Re: Request the top area of this slab?

yongler — Fri, 01 Nov 2024 01:42:29 GMT

I want to create a GDL that generates a building model from slab Accessories Add Ons and calculates the area of the building.
When changing the shape of the slab, the building outline also changes, and the area data changes accordingly. The area data is embedded in this GDL, rather than displayed through labels.

Re: Request the top area of this slab?

yongler — Fri, 01 Nov 2024 01:45:53 GMT

Thank you very much！ This is exactly what I want.

!!!===求板面积，不包括挖洞的=======
data1 = 0.0
data2 = 0.0
FOR i = 1 to points -1  !!!叉乘
	 data1 =  P[i][1] * P[i+1][2] + data1
	 data2 =  P[i+1][1]* P[i][2] + data2 
 next i

slab_area = (data1 - data2 ) /2    !!!单层面积

With the calculation method, writing scripts using GDL is so simple.