Flow along surface

Hi. I have been playing around with a simple definition from another thread on morphing planar curves/patterns on to a surface. In this definition the planar pattern has to be placed in the XY plane, if they are not the morphed surface is wrong. I have been trying a bit with changing the u,v intervals. The XForm.Surfmorph has i w mapping input, but i am not sure how to get this?
I don't think that I completely understands what is going on with the bounding box....

Best regards Rasmus

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Replies to This Discussion

Permalink Reply by Vicente Soler on November 22, 2009 at 1:34pm

That's because in that example you are using polycurves (those seem to convert to nurbs curves when morphed). If you simplify them to polylines, you'll get the same result (straight lines).

Polylines are not the same as degree 1 nurbs curves. They are simply an array of points.

Btw the method you used to create a bounding box seems a bit over-engineered :P
Try this:

Permalink Reply by Suryansh Chandra on November 22, 2009 at 1:52pm

I used the bounding box to go from any coordinate space to any coordinate space.. not just world space (which is the limitation of using world space bounding boxes). But your amendment certainly is neater for an XY-UV transpose.

I knew that polylines were point arrays until they were not geometry in Rhino, and the morph component (or any other GH component) seemed to be smart enough to cast them to degree 3 curves based on surface topography.. which is what its doing really well in the example I linked to in the previous post... so I am not sure if converting to degree 1 nurbs would help... Im just trying that now...

Permalink Reply by Vicente Soler on November 22, 2009 at 2:06pm

Maybe David missed the polyline conversion, but i think i prefer it this way. Sometimes you want straight lines to remain straight. I think polycurves get converted because arcs are probably more difficult to stay as arcs after being morphed.

No need for scripting to convert them to nurbs curves. Just use the explode curve component and the curve from control points component (set degree to 1 and periodic).

I'm not sure I follow what you mean with the bounding boxes from any coordinate space. I think to do what you are referring to it's better to use the orient component.

Permalink Reply by Suryansh Chandra on November 22, 2009 at 2:06pm

Ok.. It works to convert them to Nurbs curves (now the curves on the surface 'stick' to the surface), but the data type that the GH component suggest is still 'Polyline Curve' which perhaps implies that its still a point array?

If the code running inside the curve component is OnNurbsCurve.CreateClampedUniformNurbsCurve, then the output is different from mypoly = OnPolylineCurve(On3dPointArray). The weird bit is the unpredictable behaviour of the morph component in the 2 circumstance - if its XY space, it doesn't need any data conversion jugglery, but if its any other space, it makes life a bit more complex.

Permalink Reply by Suryansh Chandra on November 22, 2009 at 2:10pm

vincente! ur replies are too quick! i realized the bit about converting to degree 1 curves without code after i posted.. so edited the post, and by the time i came up with the second post implementing your method, you had already replied!

Permalink Reply by Vicente Soler on November 22, 2009 at 2:11pm

"but the data type that the GH component suggest is still 'Polyline Curve' which perhaps implies that its still a point array?"
David should really get into this thread and clear things up. My guess it that it is a 1-deg nurbs curve, and it should say something like "Polyline-like Curve".

Permalink Reply by to] on November 22, 2009 at 2:23pm

hi vicente+suryansh

it is definitely a degree 1 nurbscurve the code inside the curve component is createperiodicuniformnurbs or createclampeduniformnurbs with the degree and points as input

-to]

Permalink Reply by Rasmus Holst on November 22, 2009 at 2:04pm

Actually my biggest problem now is that the cells, consisting from the same points, in two different volumes, one a straight box(regular), the other a twisted box(twist) with the curved surface, offcourse the cells are not the same. So if i use my approach where I use the regular cell pattern and then morph it to the twist surface, the pattern will not fit the cells i the twisted volume. This is giving me big troubles right now. If one could translate the twist pattern to the planar - extrude it - and then translate it back to the twist. Everything should fit.

Or if it is somehow possible to cut the holes in the curved surface (twist). I hope I am not misunderstanding your advice? Thanks

Permalink Reply by Suryansh Chandra on November 22, 2009 at 2:15pm

rasmus,

If you post an image, it would really help. I can't get what you are saying.

Permalink Reply by Vicente Soler on November 22, 2009 at 2:25pm

Images are always good.

@Suryansh
I just remembered. A couple weeks ago I was in London teaching GH at the AA and one of the students was an Italian girl called Betty. She told me she knew a guy that fits your ethnicity and was teaching GH at Zaha Hadid's office. Is that you?

Permalink Reply by Suryansh Chandra on November 22, 2009 at 3:03pm

Yup.. that is me. What course were you teaching?

Permalink Reply by Vicente Soler on November 22, 2009 at 3:13pm

I taught GH to the students of the unit that corresponds to the teachers Cristina Diaz and Efrén Garcia (Diploma school).