Just started with "Getting Started video's" with Rhino 6

unhandled

#1

According to the Grasshopper “Getting Started” video #5 “Creating Biarcs” I should get a clean loft at the end. I get deformed ends at second half of the loft. In the video the halves are smooth and can be joined. I’m wondering if it’s because of changes in Rhino 6 Grasshopper. grass ex.gh (9.0 KB)

Grass exer.3dm (2.2 MB)


#2

If you’d like to get clean single surface out of these biarc curves, then you’d be better rebuild resulting biarcs…

grass ex_re.gh (10.9 KB)


#3

Thank you. What Grasshopper component would rebuild the biarc curves, or do I have to bake and rebuild in Rhino? Still I would like to know why, following the video (I think exactly) I got different results?I will download your .gh file and try


(David Rutten) #5

Peculiar, it should have worked this way. In fact it would have if the final bi-arc hadn’t been in the wrong direction.
Looking into why this might be the case. Logged under RH-46055


(David Rutten) #6

In the meantime, you can fix this by flipping all the arcs using a guide-curve (i.e. the first arc makes sense, but only works if all the arcs do not depart from that initial direction too much): grass ex.gh (13.9 KB)


#7

I tried it again from scratch with leaving the 2 lines on the cplane and it worked. But in the video some points where raised at different heights off the cplane and it still worked. As soon as I moved a point (6 count) it warped at the ends of one half

PS tried it with the lines at a higher point count as well.


#8

Thank you. I will try this out


#9

Can you please explain to me how you " flipping all the arcs using a guide-curve" by adding a “List” component.


#10

It’s in his code, the part highlighted below, the Flip Curve component just before Loft:


Simple loft between two lines made by 3 sequential points
#11

Thanks. Funny how when I do the second half, with or without the List and Flip, there is a strange warp on one end but not the baked version.

from web new.gh (10.1 KB)
I’m wondering if doing this like the video in Rhino 5 will work, since the video is done with Rhino 5


#12

Just did it in Rhino 5 and it works fine as in video . It’s a Rhino 6 or the newer version of Grasshopper in Rhino 6 that’s at fault


#13

It’s not the first time this kind of SERIOUS FLAW has been revealed in going from R5 to R6. How many models created in R5 are subtly or grossly distorted in R6? All the care put into adjusting parameter values trashed. It’s very lame.


(David Rutten) #14

That’s quite likely. There was a bug in the Rhino5 Bi-Arc solver where it wasn’t able to find a solution when the tangents were anti-parallel (or some other specific case, I can’t remember the details now). I’m guessing that in the process of fixing that, I introduced an ambiguity regarding the direction of the individual arcs.