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Selecting specific points on a grid


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Hi, I'm pretty new to using Houdini but have a question and was wondering if a group node was the best solution. Before I proceed with the question is there a good website which has lots of examples of how all the nodes work, the in-built help is good but sometimes doesn't have enough information if you've new to Houdini.

Anyway, basically I have a grid of many points, I was wondering if there is a way to select particular individual points on it. Say select every 5th point for example, or select the first point on each row. I was then wanting to copy a piece of geometry to these selected points.

Thanks for any help

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Hi! my english is too bad, I think you want make a copys in diferentes points into the same grid.

Its very easy.

Look the image

You can put the numbers points to make it in "Template groups" for copy a piece of geometry in every 5th points you can write groups 1-5 10-15 20-25 etc, and you can mix groups and select unique points numbers. 1-5 8 10-15 etc...

Sorry my english, I hope I can help you.

post-3296-1231177233_thumb.jpg

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Hi,

If you want to select every nth point, change the Operation parameter from Group by Pattern to Group by Range and the Select_of_ parameter to 1 and 5. If you want the first point of each row, it will be 1 of the number of rows of your grid.

To make it procedural, you will channel reference the rows parameter (Right click on the Rows lable & select Copy Parameter) to the second parameter of the Select_of_ parameter (Right click on the second field & select Paste Copied References) so everytime you change the number of rows of your grid, the first point of each row will be selected.

Cheers!

steven

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Thanks Steven, I have given it a go, but I have a few questions. If you see what I have done so far:

houdini_1.jpg

houdini_2.jpg

At the moment if I change the range of the group in the group1 sop the template group in the copy1 sop is not updated, so the sphere's stay in the same place.

Also I was wondering if you can take groups' of a group. For example take every 3rd point from an exisiting group, also allowing this to update itself.

Thanks

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The copySOP works on point groups.

If you change the selection of the groupSOP to 'Points' instead of 'Primitives', the template field allows you to select the group.

Currently the group is converted to a point selection.

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