image sampler reduce small diameter

Replies to This Discussion

Permalink Reply by Joseph Oster on May 19, 2017 at 9:43am

There are many ways to handle this, such as defining a domain with a minimum radius or providing a list of radii that each value is rounded to.  Or you could do this - any value smaller than the slider value is converted to zero by an expression (red due to null data, but it works):

Permalink Reply by Peter on May 22, 2017 at 12:13am

Good morning Joseph,

Thank you, it sounds great and it works despite the error.

Permalink Reply by Joseph Oster on May 22, 2017 at 6:25am

The error is due, indirectly, to the 'Cull' operation that skips X & Y values <= 4.  You can fix it by applying 'Clean Tree' with 'Remove Empty = True' to the input of the image sampler.

By the way, you have some needlessly complex code after 'Circle CNR'...

First, you are sorting circles, but not explicitly by radius or diameter.  Then you divide the results by Pi, so you assume GH used diameter (and maybe it does?), but you could have sorted radius (or radius * 2) directly.

Second, instead of this:

You can do this - "-1" returns the last item in the list:

Permalink Reply by Peter on May 22, 2017 at 11:33pm

very greatly and thank you that you gave me these tips.

i'm quite a beginner and so i'm grateful for these good explanations and the best of all, it works.

Permalink Reply by Peter on May 23, 2017 at 1:12am

Joseph, i have one last question.

is it possible to add a switch or a button that i can change the black and white color. i mean, now the white color becomes a circle. i want add a switch that the black color becomes a circle without to change the picture.

do you understand me?

Permalink Reply by Joseph Oster on May 23, 2017 at 4:44am

Since the output of the image sampler is between zero and one, all you need to do is subtract that value from one to reverse the effects.  A 'Stream Filter' allows you to switch between the two values:

Permalink Reply by Joseph Oster on May 23, 2017 at 8:07am

By the way, an even simpler way to get smallest and largest values, without 'Sort List', is as follows - 'Bounds (Bnd)' followed by 'Deconstruct Domain (DeDomain)':

Permalink Reply by Joseph Oster on May 23, 2017 at 4:17pm

At the risk of beating a dead horse, setting the radius to zero for circles below the minimum size struck me as less than ideal.  Better would be not to have any circle at all in those cases instead of so many with zero radii.  This will speed up any subsequent processing you might want to do, such as making boundary surfaces for the circles.

So I re-did your code and will post it this time - with a caveat: a very long-standing, well-known bug in Grasshopper fails to save the Image Sampler component when I save a copy of your file.

Quite annoying, but there is a work-around.  Copy/paste and connect the Image Sampler from the code you posted above into the place I reserved for it.

Attachments:

• imagesamplerreducesmalldiameter_2017May23a.gh, 13 KB

Permalink Reply by Peter on May 28, 2017 at 11:33pm

sorry for my late reply.

Your knowledge is very impressive and great thanks for your help und all the fantastic Solutions.

And the Speed up is noticeable.

I have another problem, i will explain it in a few hours, perhaps you can help me again.

Permalink Reply by Joseph Oster on May 29, 2017 at 7:53am

There are MANY examples of Image Sampler code on this forum.  You might want to look around a bit and read more code first.  There is rarely a single best way.

Like this one from two days ago:

Image Sampler with rgba images
http://www.grasshopper3d.com/forum/topics/image-sampler-with-rgba-i...