Need clarification!

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Permalink Reply by Luis Fraguada on February 4, 2010 at 2:02am

The output of the divide surface changed, it now outputs points in rows organized in a tree structure. If you want to mimick the output of the old, you will either need to use a flatten component on the output of the divide surface component, or flatten the input wherever you plug in those points.

That is correct, the intervals / domains have been just made Domain. To use on a surface, use Divide Domain^2.

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Permalink Reply by cma on February 4, 2010 at 5:13pm

thanks for the reply...but as far as the divide domain2 - it does nothing when inputed with a surface...is there something else that needs to come before this as well?

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Permalink Reply by arch. ricardo guillermo liwag on February 4, 2010 at 11:14pm

can you post here the ghx definition/file you are working on.
your process seems correct, ill try to lookn on it.

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Permalink Reply by chris on February 5, 2010 at 6:43am

i am having the same issue as the o.p. it actually will work sometimes then just randomly will quit working. I actually have not been able to get it working again since. in the one i am working on its the isotrim component develops an error

I was using 05.99 but it did not work so i upgraded to the most recent release and it will work part time. thanks for the help

Attachments:

• explode-divide surface.ghx, 72 KB

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Permalink Reply by Sameer Kumar on February 12, 2010 at 12:51am

I very quickly looked at your definition... there are a couple of problems:

1. GH is not seeing your lofted "surface" as a surface but as a Brep... it does not want to accept it as an input into the subsrf component. You may be able to explode the brep into its component faces and send them through the subsrf component one by one.

2. You need to use a separate Divide Component and subsrf component for each surface. It does not like it when you put in multiple surfaces.

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Permalink Reply by rickera on February 12, 2010 at 12:07am

Same problem here. Flatten component just flattens everything into one long list. This not always very useful.

For example http://designreform.net/2009/07/rhino-grasshopper-parametric-truss/...

Solution would be much appreciated.

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Permalink Reply by Sameer Kumar on February 12, 2010 at 1:00am

When you are trying to select a single item from a tree structure, you need to use the "Tree Item" component under Logic -> Tree.

It is important to understand that the data being output by various components is structured into trees and paths. In other words, an item belongs to a path which belongs to a tree. To find that one item, you will have to first isolate the path and then select the item using the "Tree Item" component.

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Permalink Reply by rickera on February 12, 2010 at 2:09am

Thanks

I understand the concept you've explained, but it doesn't seem to clarify how you can restore the relatively straightforward methodology that the tutorial link explaining.

I have tried this in my own model (attached) and I do not get the same results.

To help everyone understand this, can you suggest what steps could be added to the tutorial link above to make it functional again?

Thanks

Attachments:

• tree problem.ghx, 295 KB

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Permalink Reply by rickera on February 12, 2010 at 2:12am

That's wierd. It works if I run the tree through the parameter viewer (as in your example). Is there a reason for this?

Regardless, larger problem persists.

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Permalink Reply by Sameer Kumar on February 12, 2010 at 11:10am

The reason is that now there are three levels of hierarchy: Tree, path and item as opposed to earlier where you only had two levels: Tree and item.

If you are trying to find a single item within the tree structure, you have to first isolate the path (or paths) and then isolate the item from within that path. To isolate the path one has to rely on Parameter viewer, which is more than just a viewer. It actually outputs the path structure... (keep in mind that the divide surface components is outputing the points, or the geometry and not the path structure). So you get to the path structure through the Param viewer and then isolate the specific path first using a list item component.

To find the item in that path, one needs to use the "Tree item" component which requires as input the Tree, the path and the index number. Keep in mind that the path is not simply a list and therefore a list item cannot be used.

The dual layer of heirarchy is actually a very positive move for GH as it enables a lot more flexibility in managing/accessing data when things get complicated. When dealing with very simple situations, it does add an extra component or two.

Understanding the data structure and being able to manipulate it is key to unraveling the potential of GH. Please feel free to ask any other questions that you may have.

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Permalink Reply by rickera on February 23, 2010 at 6:22am

Thanks for taking the time explain all that. Will take me a while to digest it now!

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Permalink Reply by Peter Allen on February 23, 2010 at 6:56am

I've been scratching my head on this one too. I used the path mapper with a definition {A;B;C;D} translated to {A;B;C} this effectively flattens the last branch (not sure if that's the right terminology) so that each path now contains all the four values instead on two as before. After that you can use the list item component as per the tutorial. I feel that I need to understand the path mapper and tree structure more...so I'm hoping for a cracking tutorial soon.

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