How to bend the branches?

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 From:  Anna Pheiffenberger (ANNA)
2981.1 
Hi this is my first post here, and might be a very un-ethical because I asked the same question in Rhino newsgroup :/ really sorry for that... but I started this project in MOI but then moved to Rhino because I thought I needed to use the UDT tools in there, but the seem quite cumbersome and difficult to work with.

So here is the question:

OK, So I got this metal ornaments that will be cut with a waterjet, I guess
it will be a aluminum sheet.

The problem I have, is that I need to render this!, now rendering this flat
is no problem, but the users are suppose to bend the branches of the tree,
to make it more organic.

How the heck is the best way for me to do this?, I am not only working with
this tree(really just for question purpose) but a lot of patterns cut in
a sheet metal that the user is suppost to bend to make organic.

I have tried using UDT tools, like BEND but I guess that is not the right
tools, than I have tried CAGE EDIT, and that works better but in a complex
pattern it's hard to deform just the part you want, I hope you are catching
my drift here:)

so please any help or pointers would be soooooo appreciated!
Anna.

P.S.

Moi is one fantastic piece of software, its so nice to work in, I just enjoy it so much. I guess I am like many, that has a rendering licence tied to Rhino, and of course Rhino is great, but comparing it to MOI it's like really showing it's age somehow, I can't describe it better than that.

and sorry again for posting this here as a copy from Rhino newsgroup.
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 From:  Michael Gibson
2981.2 In reply to 2981.1 
Hi Anna, you may want to try using the Flow command in Rhino to deform your tree.

The way flow works is you draw 2 curves, an original "backbone" curve, and then a target curve which will be a new backbone.

So for example with your tree, in Rhino draw the following 2 curves in the top view:



Now select your tree, run Flow, select the line as the initial backbone, and then select the bent curve as the target one, and it will morph your tree to be bent like the target curve.


If you want to kind of apply a bend to individual portions of your tree that is kind of more difficult, probably for that your best bet might be to convert your object into a mesh (make sure it is finely diced, using a mesh parameter like "Divide larger than" in MoI to dice things up into small size polygons throughout), then with a mesh you can apply flow to smaller sections by selecting only some of the mesh vertices you want to morph before running flow.

It tends to be easier to do kind of localized morphing of mesh data since you can just select some mesh vertices and only transform just those around.

Hope this helps,

- Michael
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 From:  Anna Pheiffenberger (ANNA)
2981.3 In reply to 2981.2 
Thanks Michael,

Yes, I need to apply to each branch, so people would bend the tree into a 3d organic shape. Do you think I should try a polygonal modeling tool, I have a licence for Modo, but I am not really efficient in subD modeling...

I wish I could do this in Moi!. Do you think you will add some deformers in the future?
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 From:  BurrMan
2981.4 In reply to 2981.3 
Hi Anna,
There is a way to do something like this in MoI. I guess it depends on the desired outcome.

I extracted the edge of your tree and joined it, then ran the RebuildCurve command with like 300 points to get a smooth, even curve. Then I created a network surface with a bunch of points in it. (The resolution could possibly be less to enable nice bending without to much work). Then I trimmed the surface with the tree curve. Then I ran the ShrinkTrimmedSrf command on the patch to bring its edges in close to the surface trim edges. THen I show points on the trimmed surface and selected a few and used MoI's rotation widget and placed its rotation point somewhere and bent the brach. Then I extruded the surface a bit.

Here's a file to see if it will do what you want and also show the steps.

EDITED: 19 Jun 2012 by BURRMAN

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 From:  BurrMan
2981.5 In reply to 2981.4 
One other note here as I revisited this after my post.

THere is another command that worked better. I used the "Merge" command on your original tree edges to unify them then I used that curve without rebuilding it. Satisfactory and faster.

Also, I created a different patch surface using only 5 lines in the direction array, so a total of 10, and was able to bend things around much easier with better results! (didnt need such finite control)

FYI
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 From:  BurrMan
2981.6 In reply to 2981.5 
Here's a better file for comparison using the lessor resolution and the Merge curve.

EDITED: 19 Jun 2012 by BURRMAN

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 From:  Michael Gibson
2981.7 In reply to 2981.3 
Hi Anna,

> Yes, I need to apply to each branch, so people would bend the
> tree into a 3d organic shape.

Well, bending the whole shape does bend each branch along with it... But do you mean something like having some individual branches curled more than other ones or something like that?

Maybe if you could describe or show a bit more about what kind of result you want it would help.


> Do you think I should try a polygonal modeling tool, I have a
> licence for Modo, but I am not really efficient in subD modeling...

Well when I was talking about converting to a mesh I was really thinking about keeping that mesh in Rhino and just using that same Flow command on the mesh.

Notice how I drew 2 curves there, which work to deform the whole shape?

If you have a mesh object in Rhino instead, what you would do would be to draw 2 curves again but just around localized areas of the mesh, and select the mesh points so that the Flow command would only impact just those selected points.

Here's an example of how that looks - here I drew 2 smaller curves but notice how they are still arranged as a "starting backbone" and "target backbone":



Also notice that I converted your tree NURBS object into a mesh using the Mesh command, using a "Maximum edge length = 1" parameter to force polygons to be created at 1 unit intervals to make it finely diced up.

Then you select the mesh and turn points on (POn command) and select just the points of the branch:



Then run Flow and it will only work on those selected points:



You will probably need to carefully handle the selection and placement of the backbone curves to avoid too much interruption between the bent part and the unselected portion of the mesh. You may also need to do some strategic smoothing (select some points and run Smooth on them) if there is some roughness between the bend and unmodified areas.


Of course doing things in a sub-d modeling package would also work pretty well for this kind of deformation stuff.

Just in general polygon mesh data is more friendly to mushing / squishing / morphing type manipulations, particularly if you want to apply such things to specific localized zones of the model.


> I wish I could do this in Moi!. Do you think you will add some
> deformers in the future?

I do hope to add some in the future, but it is hard to know exactly when.

It is a difficult area to deform a solid that is made up of many trimmed and joined pieces and still have the joined edges stay connected to one another within tolerance.

- Michael

EDITED: 10 Oct 2009 by MICHAEL GIBSON


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 From:  Anna Pheiffenberger (ANNA)
2981.8 In reply to 2981.7 
Thanks everyone, I think Michael approach gives me the most options,

Yes I was meaning that I want to give each branch its own curl, each one unique... like... bend a little and twisted a little.

Sorry for being unclear, but what a help I have got!!!! thank Burrman and Michael

Anna.
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 From:  Michael Gibson
2981.9 In reply to 2981.8 
Hi Anna no problem!

Another possible way would be a more "construction from wireframe" kind of approach where rather than surface deformation.

That would look something like this:

Draw a line across the base of the branch. Then run Edit/Trim to slice the branch off as a separate surface. Select the outer edge of the branch fragment and use Copy/Paste to duplicate it and then delete the surface, which leaves just the curve portion like this:



Now turn on control points of the curves and move them around in the Top view to give it a kind of bent shape. Avoid manipulating the points nearby the cut, you also may need to insert some more control points in that area so that it won't be affected when you pull the other points around.

Once you have the curves bent, use Edit/Trim to cut them into 2 pieces like this:



Then use Sweep to build a new surface there:



So that's a different approach where you're kind of breaking off the branches and creating replacement ones.


Also sometimes with this kind of a thing it may be good to actually make the new branch come to the base at a sharp angle and then use Fillet to round off the connection rather than trying to keep it smooth more manually.

- Michael

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 From:  Michael Gibson
2981.10 In reply to 2981.1 
Hi Anna also for mesh deformations (and other methods too) you may want to possibly try working on just a single surface rather than the thickened solid, and only get it into a solid with thickness by doing an offset/shell type operation at the end after you've got it all set up.

- Michael
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 From:  olio
2981.11 In reply to 2981.10 
Thank you Michael,

I can't believe I have not posted here before, now you won't get rid off me:)
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 From:  BurrMan
2981.12 In reply to 2981.10 
Boy that Rhino has some powerful commands in it. I really should invest some time in learning it as a companion for MoI!
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 From:  ed (EDDYF)
2981.13 
.

EDITED: 13 Mar 2010 by EDDYF

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 From:  jbshorty
2981.14 
Hi Anna. Using the methods already mentioned by Michael G , I see no reason you can't keep this as Nurbs when you deform the branches. Just create your flat trimmed shape. Split off any "limbs" by using a line as the splitting object. Run flow as MG described or even use the bend command but be careful that your bending spine is perp to the splitting line and that the bend starts a short distance inwards from the edge of the split, this will keep tangency of the seperate pieces. Bend takes a bit getting used to but good results are super easy once you got the hang of it and you set the Cplane properly to the bending plane. If you decide to use Flow the be sure to set the "stretch" option to "no" so the bent limbs will be accurate size after flowing. Then you could join the nurbs parts, thicken (shell) in MoI or Rhino 5...

Alternatively, you could model this in modo. Just divide a subd mesh to a high-res version and use the bend tool in conjunction with a weight map or falloff to control the localization. But would be difficult to keep the accuracy of the flat production form versus the subd form...

Another idea if you decide to model in subd is to rig a flat high-res mesh with bones in an animation program. A simple weight map could restrict the bent areas to selected regions. Then you're ready for some animation too... hmmm... I'm picturing a bad (really bad!!!) Eddie Murphy movie circa the mid-1980's with a dancing soda can... :•)

jonah
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 From:  okapi
2981.15 
Since you mention that you also have modo,
I would recommend you do this with subd. It will be much easier to control.
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 From:  Anna Pheiffenberger (ANNA)
2981.16 In reply to 2981.15 
The only problem I see using modo, is modeling this 2d shapes or complicated profiles that gets extruded to some thickness...is there something I am missing in modo or are these things just simpler using moi?
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 From:  Anis
2981.17 In reply to 2981.16 
Hi Anna,

Also you have consider that Modo only handle polygon data as I know.
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 From:  okapi
2981.18 In reply to 2981.16 
right, it is much easier to get precise shapes out of moi.
But it seems you want to have some 'soft' control as to how the shapes are bent, and here modo seems more appropriate.
I like using both apps, depending on the specific task.
in modo, you should create your 2d shape first, making sure you have a god edge flow (use only quads),
after you give your shape some thickness you can either use
edge weights , or use minimal edge loop bevels or extrudes to get a hard shape.
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