unroll help please rhino

[lazeyjack]

when I unroll this in Rhino
1 I can not see the unrolled in window
2- it says 100%smaller in unroll, it also gives area of 60 million sq/m even though the scale is right in my dwgs, the l of this plate is about 6 m
thanks Stu

[CGN]

check the units that may be causing the problem

[terhohalme]

Read Help topics! Start the command and pres F1. You can unroll only developable surfaces.

For future, use X axis for length, y axis for width and z for height.

Millimeters in units are OK.

[duluthboats]

You will need to change that nice round bilge to hard chine. I find the most accurate unrolled surfaces in Rhino are made from a straight line swept along two curves. If the surface can not be made this way, you won’t get a good unrolled surface.
Gary

[CGN]

Duluthboats
There are two features in Rhino for developing plates, 1 is for developed surfaces which is integral in rhino and then there is the new feature that develops double curvature surfaces, this is the one i mentioned i don't think they are supporting much, maybe steve can let us know more about what are they doing with it.

Lazeyjack

If you are not using the right command then you won't be able to roll your surface and is basically crashing because can't find a solution for double curvature plate or surface.

Ok i found it this is the name of the command and the link

http://en.wiki.mcneel.com/default.aspx/McNeel/AdvancedFlattening.html

Shipconstructor is able to do that but they "pull the plug" for some reason to the plug in that they use to sell for Rhino.

[duluthboats]

Thanks CGN,
I can't seem to keep up these days. I will have to give Squish try.
Gary

[duluthboats]

Lazyjack,
Squish seems to work fine on a nice clean Rhino surfaces. I could not get it to work on your surface. I tried to rebuild it but failed. You would have to reconstruct it in Rhino and rebuild it to the minimum number of points needed to define the surface. Then Squish will flatten the surface. Cool!!! ;-)
Gary

[lazeyjack]

thanks you guys, my head is spinnin' but then again that does not take too much rhese days
that surface was made autoship,
i took it into maxsurf workshop and it did unroll it, but as two surfaces and for the life of me I could not see a way to join them
I found that sometimes workshop opens things and sometimes not Comes up with random stuff like" cant open as was created with later vs workshop," which is not the case

[MikeJohns]

The problem is that it is 68 surfaces joined. You probably need to explode the surface and then try rebuilding.....


I just did this and unrolled-developable surface on the lower hull here's the file.

Usually best to unroll different parts rather than all at once, otherwise the double curvature will tend to give poor results.

cheers

[lazeyjack]

lo there Mike
thanks, I can not open cos I have rhino 2, , :))
I built 4 of those, once, the long way, as I said I managed to open and unroll in workshop, workshop seems unstable as far as opening files goes, same type, sometimes will sometimes wont
In this Pic I am somewhAt younger, but as tired!!!later I got rid of the last stringer and went 4 girdars with those deep floors, that way I could offer 10 years hull warranty, they are all 15 yrs old now, no probs and used hard offshore in NZ
Stu

[MikeJohns]

Re-tired .... just tired again. Afternoon naps are good :)

I re-saved that file as a Rhino 2.

For all the ease of Workshops features it can be a pain at times, which version of workshop?

cheers

added
Looks fit and able....the boat too! I like the floors.

[Willallison]

Is the Squish comand only for Rhino 4?
I've been having trouble unrolling an irregularly shaped (but otherwise flat) surface in Rhino 3.
Any suggestions would be most welcome:D
I'll try to post the surface later tonight.....

[duluthboats]

It is a beta tool for the latest Rhino4 version. I can try it for you and show you the results. I'm at work now. I will have to try in the AM. Or maybe someone else will try it.
Gary

[Willallison]

Thanks Gary
I've attached the offending surface (well, polysurface, actually).
It's currently made up of two surfaces. I tried exploding, unrolling, then re-joing, but that didn't work.
Essentially, the longest side is parallel with the sheer and has slight curvature, but when unrolled this is shown as completely straight. Also, two edges down near the bottom that are parallel when unrolled become unparallel.
This panel is already flat.... it's got me bluffed....

[duluthboats]

I had some trouble with it also. I rebuilt the surface so I may have changed something. When I used the squish tool it distorted .03% so the new surface should be very close to the one I rebuilt. When I used the unroll tool things got crazy. The red surface is UNROLL and black is SQUISH. Big difference:eek: I hope I got the attachment right.
Gary :D

[Willallison]

Thanks Gary - at least it looks like the original surface now!:D
Interesting to to note that your unrolled surface looks quite different to mine.... mine bears a closer resemblance to the original surface - close enough that I alsmost missed the difference - which makes me nervous about some of my other panels...
Is there any way of checking it's accuracy to the original surface? (Other than building it in very expensive cnc cut frp/foam panels that might not fit!)
I've also sent you a PM

Thanks again...

[duluthboats]

Surface area is one way that might help check. I don't have much time now but will look at again in the AM.
Gary

[lazeyjack]

Surface area is one way that might help check. I don't have much time now but will look at again in the AM.
Gary

you could check in workshop maxsurf and compare,

[Willallison]

Thanks LJ - I have considered doing that, but I know that transfering between programs can introduce errors ... still... worth looking at.

I compared surface area's, as Gary suggested:
Original surface was 1955058.61 sq.mm
Gary's squished surface 1955134.96 sq.mm
Which at 1st glance appears to be quite a differenec, but is in fact only about 0.2%

This got me interested, so I compared a number of those that I've unrolled to their originals. In all cases the unrolled surfaces are marginally larger, but all by less than 0.3%. This would suggest that, so long as the basic geometry is the same, the unrolled surfaces could at least be trimmed if necessary to fit.

Comparing the perimeter length showed the squished and original surfaces to be within 1mm of each other, however, so perhaps it is indeed the geometry that is slightly different. I wonder though if it's any less accurate than one would achieve by doing it the old fashioned way - by hand - or indeed if it's more accurate...

I also compared the areas of unrolled and original surfaces that were already horizontal (and flat). In these instances the differences between original and unrolled surfaces were negligable...

[dougfrolich]

I think that the issue with unrolling your surface is that it is not a fair, and developable surface. Use th surface analysis tool to see what I mean, set it to auto range and Gussian.
Doug

[duluthboats]

I played with it some more. Here is your original surface unrolled no other changes. And here is that surface rebuilt and squished. I overlaid them and there is very little difference, just less than 3mm from one end to the other. I think they are very close to what they should be. I would go with the original and unroll.
Gary

[Willallison]

Thanks Doug. The polysurface is in fact made up of two smaller surfaces. I had checked the fairness of the larger and more irregular of the two (which is ok) I didn't bother checking the smaller one as it (should!) simply be a flat plane derived from the 1st one. Lesson learned....
However, there was still an obvious difference between the original and unrolled versions of the larger of the two - though Gary's efforts seem to have been more succesful than mine....

[Willallison]

Ok - now this is just getting silly!:mad:
Due to the unfairness, I re-constructed the surface and tried unrolling once more. As you can clearly see in the attached file, there's a considerable difference between Gary's and my unrolled surfaces. Where Gary's accurately reproduces the curvature of the sheer (the top edge of the surface) mine straightens it out. And edges that were (and should be) parallel are now not....
I'm sure this is more a shortcoming in my Rhino prowess than a failing of the program - but it sure is bloody frustrating!! :mad: :confused: :mad:

[Willallison]

By Jove, I think I've done it!:D
After some very patient (and much appreciated) help from Gary, I think I've had at least partial success. For those interested, and in the hope that it may help others (and I guess so one of you can tell me what a twit I am if it's wrong!;) ) I'll describe what I did.
Essentially, this surface is a vertical plane - albeit a rather irregularly shaped one. I reconstructed the surface by extruding vertically down from the top edge (the sheer) and then trimmed to match my orginal surface.
As I described above, this still failed to unroll successfully.
So, per some of Gary's instructions (for reasons I shan't go into here, I couldn't carry them out to the letter) I duplicated the edges and constructed a new surface by using the Patch command. I then rebuilt this surface with only a few points. Unrolling this surface gave (what at least appears to be) the correct surface - and one that matches very close to the one Gary kindly made for me.
Quite why one needs to construct a new surface and rebuild, rather than simply rebuilding the original (tried that...) I can't figure, but hey, success is its own reward as they say, so if you'll excuse me I'm going to go do a little jig around the room:p

As always, thanks to all...

[lazeyjack]

Will I am cracking up I have been strugglin with Rhino for a year, but my tutor is very patient I could have lofted a squillion boats longhand whilst I have bin piddlin' around avec Rhino

[Willallison]

:p Glad my trials and tribulations are of at least some use - you will be further amused then to know that I've moved on to another surface...

It's worse!!!!:P

[lazeyjack]

measuring lengths and stuff:)) I know I can only get within 4mm, how can I reset, looked most places