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Monday, February 9, 2009

Flowing objects along a surface


Learn how to use the command FlowAlongSrf in Rhino to morph any selection onto a target surface.

26 comments:

aubergine2001 said...

Thanks, I have been using this 'Flow along surface' lately and this is a good tutorial.
I would suggest using the UV to extract a surface into a flat planar surface for the objects to be flowed. This helped me a lot when I found this out.
Anyway to have rigid always on in the Flow options ?

Brian James said...

Hi aubergine2001,
Thanks for the feedback! Matching UV parameters between the base and the target surface can surely be helpful as well with FlowAlongSrf.

You can write a command macro to always use the rigid option in Tools>Options>RhinoOptions>Aliases... choose a hot key/alias and then type this as the command macro
! _flowalongsrf pause _rigid

Laurenn said...

Just fell upon your blog from Core77. It's awesome, I'll be subscribing to your blog from now on :)Looking forward to more tutorials :D

Raijv said...

Hi,
Nice tutorials Brian, really helpful, I too write few tutorials for rhino and autocad, hope all likes it.

here is the link :

http://product3d.blogspot.com

Regards
Rajiv

chilli said...
This comment has been removed by the author.
chilli said...

The video was really helpful. I am very new to Rhino and I have been trying to create a skin for one of my projects that would be result of its response to the climatic conditions of the place specially the sun...how should I go about this? do you have any suggestions? is there any resource that I might tap into for some guidance?

Thanks

Brian James said...

Hi,

Thanks for the comment. I think the Grasshopper plugin will give you the power to do what you want. You could for instance change louver angles or window apertures in relation to a vector representing the sun angle. You can dive into GH here... http://www.grasshopper3d.com/

I've posted a few tutorials on this site as well which may help get you started.

Thanks,
Brian J.

Anonymous said...

Very amazing tutorial.

Question though: I can't seem to use FlowAlongSrf for circular surfaces. In my case, I want to flow objects on what looks like a frisbee turned upside down. It produces the weirdest shapes when I try this command with that. I'm guessing it's because there are no corners for Rhino to orientate on, it's not advisable to use this here. What I would need is something like a "FlowArrayPolar" type of command. Would you have any advice on how to go about this?

Brian James said...

Apologies for the delay in response Anonymous. All surfaces can be thought of as four sided sheets of graph paper. The two directions on the paper are still there even if the surface is trimmed into a circular shape. This is what FlowAlongSrf is looking at. You might consider making your circular surface as a revolve or 2 rail sweep instead to produce the result you are looking for.

lille j said...

Is there a way to use flow along surface in rigid mode, without making the objects change orientation? I want to lower objects on an uneven surface, but avoid that their bottom aligns itself with the direction of the surface.

Brian James said...

Hi Lillie,

Try the Rigid option in the command line. I think this will do what you want. OrientOnSrf also may be what you're looking for.

Radu Architecture said...

Hi,

Thank you for the tutorial.
My surface is a revolved curve and when I flow along srf the objects on the rectangular base (as the "unrolled" or UV surface) the first objects and the last objects on the base do not connect on the revolved surface, i.e. there's a gab between them as if the rectangular base couldn't be stretched enough. Any suggestions?

Radu Architecture said...

Hi,

Thank you for the tutorial.
My surface is a revolved curve and when I flow along srf the objects on the rectangular base (as the "unrolled" or UV surface) the first objects and the last objects on the base do not connect on the revolved surface, i.e. there's a gab between them as if the rectangular base couldn't be stretched enough. Any suggestions?

Brian James said...

Hi
I have two thoughts that may be what you need. The first is to use the stretch option in the command line when using the command. You could also enable history and then adjust the base surface to change the resulting flow. Measuring the length of your base and target srfs before the flowalongsrf can also help.

@RhinoGuide

Anonymous said...

Hi,

It seems if the surface to flow along is splitted or cutted from a bigger surface, the objects will flow along the bigger one instead. I'm new to Rhino. Pls also help to let me know how to have a 'clean' split or cut of the surface, without having such a 'memory' feature.

Thanks!

Brian James said...

Try the command ShrinkTrimmedSrf if you are flowing onto a trimmed surface. This will shrink the control point structure into the smallest rectangular boundary. The control points are what the Flow will follow.

Anonymous said...

hi
sorry for my english :)
your video is very helpful but i have a problem with the command "flow along a surface". when i try to use it, the objects have not the same orientation as the curved surface..
i don't know if you understand, as i cannot send you a picture :)
thanks in advance!

Brian James said...

Hi,
This sounds like the corners picked on the base surface versus the target surface are causing the flowed objects to be on the incorrect side. Try running the Dir command on both the base and target surface first to determine which corners correspond to one another. The U, V and normal directions should match up between them.

Anonymous said...

Hi,
Sir, do you have any suggestion on how i can flow objects along a surface accurately?

Brian James said...

Hi,
Accuracy can be thought of in terms of matching the target surfaces curvature or maintaining the shape of the base pattern. It is often impossible to do both given doubly curved target surfaces but there are methods to increase accuracy. I would suggest looking at two plugins in depth, Paneling Tools and Grasshopper which can be used to control the results further.

Anonymous said...

Hi,
I'm normally pretty confident on Rhino & have been using flowalongsurface successfully for a while now, that is until today.
The problem that occurred is I implemented said command using a mesh model to flow along a surface as usual and it flows along but now the mesh is a weird patchy version of it's self. & I have no idea how to solve this. any help would be greatly appreciated? many thanks

Brian James said...

Hi,

That sounds like maybe a bad render mesh but if it was a mesh object already prior to the flow then it might be self intersections effecting the shading. I'll need the model and a screen shot of what you see. Both with before and after versions. Can you email this to tech@mcneel.com ?

Alejandra Gonzalez Born said...

Hi,

for some reason when i use the flow along surface on a curved surface it does it alright but in the wrong face of the plane. I dunno if i make myself clear. I have my pattern over a plane, and then i have.. let's say a tube.. i want the pattern to turn around the outside of the tube but when i "flow along surface" it does it on the inside... I've tried flipin the surfaces but it's the same, any thoughts??

Brian James said...

Hi Alejandra,

It probably has to do with the UV directions on the base surface versus the target. try the Dir command and check out if they match. Send the model in to tech@mcneel.com if it's still not working for you and I'll take a look too.

Guppu Baba said...

The objects I want to flow are asymmetrical. The path I want it to flow along was cut from another polysurface.
If I attempt to flow the objects along this surface they take the path of the previous polysurface. How can I alter this issue?

Brian James said...

I think I understand but it would help to see the file or screenshots of the target surface and it's control point structure. FlowAlongSrf is going to use the ctrl pts so if you flowing onto a trimmed surface, you'll need to trim the result or use another method of patterning like the Paneling Tools plugin which may help depending on the objects being flowed. Please post to the Rhino user forum if you can for more feedback from users http://discourse.mcneel.com/