The Global ARCHICAD Community

Stay informed. Get help. Share your knowledge.

Everything about GDL - Doors/Windows/Objects/Stairs etc. (Example: I created an object that prints an error message in 3D all the time, please help!)

Moderators: Karl Ottenstein, LaszloNagy, ejrolon, Barry Kelly, gkmethy, Gergely Feher

By JGoode
#303555
I have list of potential options in an object that I would like to have change whenever our template is opened. The easiest way I thought of was to just use rnd to pick between 0 and however many image options that we have. However it doesn't refresh when a new instance is opened or if I use SHIFT+CTRL+ALT+R like I want it to.

Is there any way that I can get this to work as intended? Is there a way to automatically create a new RND number whenever the object is 'Updated' or 'Refreshed'?

Thanks
User avatar
By David Maudlin
#303571
JGoode:

If I recall correctly, this function does not generate a random number, it selects from a predefined list of numbers, so the initial result is the same. When needing randomness, I have used something like the third decimal place of the object's x or y location (seemingly random number between 0 to 9) to generate a random number.

David
User avatar
By Karl Ottenstein
#303572
I recommend reading this thread from 2004 - little has changed since then, but two solutions are given for (pseudo) random object behavior. (The main change since then is a limitation on what can appear in the parameter script etc)

viewtopic.php?f=6&t=2191
User avatar
By Lingwisyer
#303677
The solution proposed over on the GDL forums for anyone who stumbles into here.

Péter Baksa wrote:RND returns the same sequence of random numbers in each run. The sequence is different for each placed object. This makes it possible to create randomized objects (eg. trees) that look the same on different 3d views (different sections, animated fly-through rendering).

It is possible to get the time using REQUEST(“DateTime”,…).
You can convert the returned string to a number with SPLIT.
Use that in a loop to get different number of random numbers in each run.
Code: Select all
n = REQUEST ("DateTime", "%S", datetimestring)
split(datetimestring, "%n", rndseed)
for i = 1 to rndseed + 1
	random = int(rnd(100))
next i
text2 0,0, str(random, 1, 0)

Which I assume that you then pull a number from.