Newbie Sweep1/2 question

Original photo:

First attempt to model the same chair cushion

The next step is to introduce a groove on the seams (illustrated by the red Pipe)

The groove/fold/crease created by a Pipe with a BooleanDiff produces edges way too sharp, and I plan to Sweep1 or Sweep2 a smoother profile:
sweep_profile_

Question1: how do I position a custom Sweep profile (cross section curves) to run along the rail/edge and keep it somewhat tangent to both connecting surfaces?

Question 2: Is there another simpler way to make a smooth groove in a solid?

Thank you,

Arsen

try with edge softening instead of modifying the geometry.

If you need to fillet, then Split away the fillet part with a pipe and put a “helper target surface” in the middle of the two fillets, then blend the fillets towards the helper surface…

// Rolf

RIL, thank you and please bear with a newbie here.

I would absolutely love to have an edge “in the middle of the two fillets” for the purpose of unwrapping the geometry later along the new seams.

How do I create a “helper target surface” in the middle after I split the surfaces with a Pipe? I can FilletEdge and BlendSrf parts later.

Thanks, Diego.

If you mean shutlining or any other rendering tricks for edge softening, I cannot use them - I use V-Ray plugin in Rhino for the final renders.

Arsen

Try something like this:

Wider blend looks better (tangent, tangent in this picture)

// Rolf

1 Like

Rolf, this is the solution I was looking for - the crease/fold looks perfect. I understand the concept on the 2D plane, thank you for the illustration.

Now I just need to figure out in which direction to extrude and move the HelperSrf for the cushion as a whole in the 3D world. Should I do one side at a time? And then manually fix the geometry at the corners later?

Thanks again for your time and patience.

Arsen

Hi Arsen - if you extrude the curve before making the pipe & trimming, i.e. while the curve still has the surface under it, you can use the Fin command (Extrude curve normal to surface) to set what will be a useful direction in many cases.

-Pascal

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Thank you, Pascal, this is a great hint - Fin is fantastic with creating a normal extrusion to a surface.

What would you recommend with the corners of my cube (cushion) after I complete the sides? Manual blending for all?

Hi Arsen - I think I’d trim those surfaces with a BlendCrv and then carry on with Fin

image
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BTW, a cheap way out is to FilletSrf to a fin, then trim

image

-Pascal

Thank you, Pascal - I am working on it.

Hi Arsen,

Instead of actually modelling the creases, you can als try and see if the Shutlining feature works for you.
https://docs.mcneel.com/rhino/6/help/en-us/index.htm#properties/shutlining.htm

-Willem

You can extract the resulting render mesh (ExtractRenderMesh) - V-Ray should probably be able to use that…
-wim