What does the "Initial Value" of the "Like This" function indicate?

Generative Design
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1

I am using Generative Design in Revit.
I have a question about the “Like This” option when creating a study.
In “Like This”, the initial value is set to create a study.
I thought that the starting value mentioned in the URL below refers to the initial value, but I was wrong.
https://help.autodesk.com/view/RVT/2024/ENU/?guid=GUID-887BCC49-06E9-4C52-AECD-BE92646DF2F5

For example, if I set the initial value to 500, the help article says the range should be 400 to 600. However, in reality, results from 300 to 700 were displayed.
I would like to know the relationship between the initial value that can be set on this study and the starting value mentioned in the help article.

2

Some info here on the study types: https://www.generativedesign.org/02-deeper-dive/02-01_algorithms/02-01-04_solvers

The like this will take the initial value and get a random sampling from 20% of the domain below the initial value to 20% of the domain above the initial value. So if your variable range is 0 to 1000, 20% is 200, and the initial starting value of 500 would result in input values between 300 and 700.

1 Like
3

Thank you for your reply.
So, am I correct in understanding that if I choose Like This, the Generative Design will be done at 20% of the maximum value of the variable range?
(like 2000*0.2=400 if it was set from 0 to 2000)

4

Correct.

2000 possible options results in values 400 below or 400 above the input value.

The simulated math result would be

sampleSize = 10;
size = 2000;
inputValue = 1234;
range = 0.2 * size;
random = Math.RandomList(sampleSize);
offsets = random * 2 * range;
adjusted  = offsets - range;
studyValue = inputValue-adjusted;
1 Like