Extracting Reparameterized Isocurves with Python

Replies to This Discussion

Permalink Reply by wil on October 17, 2015 at 7:39am

It's because AddPlanarSrf creates a trimmed surface, which takes the UVs of the "untrimmed" surface, not what you actually see there.

A way to get around it would be to replace (line 17):

boun_srf_plot = rs.AddPlanarSrf(i)[0]

With:

boun_srf_plot = rs.AddNetworkSrf(rs.coercecurve(i).Explode())

Not guaranteed in all cases, but should work for you here.

Permalink Reply by Andrew M on October 18, 2015 at 8:49am

Thanks, that solved that problem. Very useful to know. But now for some reason I cannot get the full list of isocurves to extract. I've set my 'xrange' and 'yrange' variables to generate uv extraction coordinates based on the input sliders. This works perfectly when they output to the native Grasshopper isocurve components, as shown. But I can't get them to successfully feed into the extractisocurve function in my script. Is there a simple way to replicate what the Grasshopper isocurve components are doing in this file?

Thanks for any help!

Attachments:

• Extract Isocurves on Reparameterized Surface-2.gh, 8 KB

Permalink Reply by Andrew M on October 19, 2015 at 8:50am

Basically I see the problem as not being able to iterate through my list of 'xrange', 'yrange' values when evaluating the surfaces. I can choose any of the individual values by stating, for example, xrange[0], but not all. 

If my 'xrange' list of u values is:

{0.8, 0.0, 0.0}
{0.6, 0.0, 0.0}
{0.4, 0.0, 0.0}
{0.2, 0.0, 0.0}

and 'yrange' list of v values is:

{0.0, 0.8, 0.0}
{0.0, 0.6, 0.0}
{0.0, 0.4, 0.0}
{0.0, 0.2, 0.0}

Then how would I be able to evaluate each surface for each of these? The following will not work:

myisolist = []

for i in plot_surface:

myiso = rs.EvaluateSurface(i,xrange,yrange)

myisolist.append(myiso)

Thanks again to anyone who could lend a hand. 

Permalink Reply by wil on October 19, 2015 at 9:04am

Do you want to iterate over all of the u & v values for each surface?

Try something like:

for srf in plotSurface:

    for u in uRange:

        for v in vRange:

            myIsoList.append(rs.EvaluateSurface(srf, u, v))

Permalink Reply by Andrew M on October 19, 2015 at 9:48am

Hi wil, ah yes, that makes perfect sense. I will try this when I get to work. To extract each isocurve, would I then just continue this as follows?:

for srf in plotSurface:

   for u in uRange:

      for v in vRange:

         myIsoList.append(rs.EvaluateSurface(srf, u, v))

         for i in myIsoList:

            myIsoCurves.append(rs.ExtractIsoCurve(srf, i, 2))

Permalink Reply by Andrew M on October 20, 2015 at 9:07am

After trying many different methods, I cannot get these isocurves to extract. I thought a data tree structure was avoidable, but if it is not (I'm receiving ironpython.list errors, which I hope my correct curves are hiding in), I've tried to implement a data tree structure without success. What am I doing wrong? I've began to have dreams (nightmares) in code, haha. Thanks so much to anyone who can help me solve this, I'm sure the answer to this will pave the way to a greater understanding for how GH and Python work. 

Attachments:

• Extract Isocurves on Reparameterized Surface-3.gh, 13 KB

Permalink Reply by wil on October 21, 2015 at 2:37pm

I've attached an example to show how data trees work inside python. It's a little more complicated than it needs to be (especially considering how simple it is to do with the gh component) but it should show the concept well enough.

Attachments:

• ExtractIsos.gh, 20 KB

Permalink Reply by Andrew M on October 22, 2015 at 8:13am

Thanks wil, that's what I was struggling with. I need to take some time and absorb this data tree syntax. Much appreciated.