move points in a trigrid

I'm looking for a better way to manipulate the points in a trigrid - i have a hack work around but it involves using a delaunay mesh and my triangles' position in the list end up getting shifted in ways that arent really useful. I need to be able to pull out triangles with a culling pattern but it's impossible given its current state.

Is there a way to move shared vertices together, as a single point, rather than as separate per-triangle vertices?

thanks

Gabe

Replies to This Discussion

Permalink Reply by Gabriel on October 6, 2011 at 3:43pm

when i say points, I mean the vertices of the curves. i want to use a series of move-transform components to operate on the vertices but I want them to act in sync - as far as I know I need to explode or retrieve the points and then transform them, only to rebuild the triangles in their original sequence...again, there has to be a better way

any ideas?

Permalink Reply by Gabriel on October 11, 2011 at 2:44pm

ok. i suppose an image might be necessary. i have a grid, a triangular one, and I want to move each vertices a certain distance but I need shared vertices to move together AND I need the original order of the triangles...anyone?

Permalink Reply by taz on October 11, 2011 at 8:25pm

How are you moving your vertices?

You could use Kangaroo. Daniel's recent metaball video would be a example...

Permalink Reply by Manuel on October 11, 2011 at 9:45pm

Hi,

I dont know how you are doing the triangles, but you can recreate the conections from the delaunay using the connectivity diagram like this:

in the example i use random values to move the original points... but the important part is the list item using the index from the delaunay, the line between the point and the points from the list item and a remove duplicate lines from kangaroo plugin.

Permalink Reply by Gabriel on October 11, 2011 at 9:58pm

Thank you taz.

The vertices are being used by breaking down by converting the triangles into faces, creating a joined brep, then exploding for single vertices - its a tototal hack. From there I just move each vertices at least tostart with a random value. I actually want to stay away fom delaunay because I prefer the order of a trinagular grid - it has a data tree making picking out the triangles real easy.

I will try your suggestion when I'm not on this blackberry but I really need the control of being able to choose the triangles in an orderly way

Permalink Reply by Gabriel on October 11, 2011 at 10:22pm

sorry, thanks manuel as well

i have to try what youre suggesting but i think its missing what im after. i start with a regular trigrd. i move the vertices but I want to reassemble the exact same triangles - i want to avoid a delaunay mesh or drawing edges - unless of course I can draw edges or whatever in an order that resembles the trigrid...

Permalink Reply by Ola Jaensson on October 12, 2011 at 1:51am

Try this:

Permalink Reply by Massimiliano Trave on October 12, 2011 at 4:40am

hi Ola.

Do you can explain me how do work in this code replace string component?

Thanks in advance.

Permalink Reply by Ola Jaensson on October 12, 2011 at 6:03am

I treat the coordinates as strings and replace the ones that are identical to the point I want to move with a string defining the new position. A bit cleaned up:

Permalink Reply by Gabriel on October 12, 2011 at 7:14am

thanks OLA!!! this looks very promising. i want to move multiple points but I think this should do it.... I've never used the search and replace string component so this is great entryway. thanks so much!

Permalink Reply by Gabriel on October 12, 2011 at 8:00am

Ola - I have tried to take away the Branch Item part, so that it's operating on all branches but then the problem becomes that the search and replace is only operating on separate branches so vertices are not moving in unison...any workarounds?

Permalink Reply by Ola Jaensson on October 12, 2011 at 9:43am

I am not sure I understand what you are trying to do. Can you post an image or some code?

The Replace String component doesn't seem to work with multiple inputs for F and R.