SubD Tutorial - Creating SubD objects

A new SubD tutorial is available as a Rhino LayerBook.

Download the SubD Tutorial - Creation.3dm, open it in the latest Rhino WIP, and follow the instructions.

This tutorial is a simple overview of ways you can create new SubD objects.

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Hi @dalelear
Never knew about layerbook … Has that been in there for long or is it a new thing?
And great overview - thanks!
-Jakob

EDIT Sorry - just saw the announcement of it being a newly added command - please disregard :slight_smile:

Is it possible to reduce the number of SubD faces? (or “density” ow whatever defines the structure of a SubObject).

// Rolf

Rolf asked:

Currently, no. In the longer term, yes. This issue is on our SubD todo list as RH-52279.

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Would ot be later possuble to switch between SubD and low poly representation easily and fastly?

I am used to low poly modelling and then subD would be a preview I eould like to switch on from time to time

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Hi, @Petras_Vestartas

Yes, it would be possible, but that adds complexity to the workflow and can introduce confusion. It sounds like you are comfortable switching between something like a control net, perhaps with 1 or 2 subdivision steps applied, and a limit surface view.

I also understand that in this is a common subdivision “feature” going back decades. It is my understanding that some of the contributing factors were typical computer resources were more limited and limit surface evaluation was not widely understood or correctly supported in some products.

One technique I am familiar with is for a designer to want to modify control net locations at an early subdivision level.

In your experience, what is gained in your workflows by switching display modes? In particular, do you feel anything is gained by working with SubD where the display is showing 1 or 2 levels of subdivision?

Thank you Dale for the reply.

The main point for switching display settings is that it is much easier to draw rectangle mesh face ,and add mesh faces during the modelling rather than moving control points. The advantage from such interface is from user perspective as it is more about modelling the low poly geometry and SubD is a smoothed output.

At least this is how I understood it .

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I agree with the view that flipping between the polygonal and SubD representation is important.

I’ve noticed that if you turn on control points for a SubD object, the control polygons are visible as control points and dashed line edges.

I wouldn’t mind just editing the SubD vertices, edges and faces and then seeing the results in the “control points on” polygons.

The main problem I have is there is no way to add or remove edge loops to a SubD object (I assume this will be coming). I have to work around this by keeping a mesh object around for editing and then converting it to a SubD to check that the shape is right.

John

Yes, it would be nice just select mesh face, delete it and draw more meshes, which is the cage from SubD.

Hi, @Petras_Vestartas and @ajohnblack

Thank you for the additional information.

For deleting and adding faces to a SubD, here is an extremely clunky workaround you can use in the current build until something better is available:

  1. To delete faces, work in a shaded view, while holding down ctrl+alt click on the faces you want to delete. When you’re down selecting, press the delete key.

  2. Select the SubD and type PointsOn. Use 3dFace or other mesh drawing tools to draw new n-gons.

  3. Select the n-gons you made in step 2 and type Join. This joins all the n-gons into an ordinary mesh.

  4. Select the mesh you made in step 3 and type ToSubD.

  5. Select the original SubD and the one you made in step 4 and type Join.

  6. Add and remove creases as needed using the Crease/RemoveCrease commands. The Ctrl+Shift + click on edge sub-object select technique is useful in this step too.

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Here’s some unexpected behavior when trying to cap a subd (just out of curiosity, I wasn’t expecting this to actually work)
Before cap command on a subd from an extruded curve:


After cap command on subd:

I’m noticed a strange problem capping a subD shape today.
Basically I drew a polygon and extruded it as a subD. Then I created a capping top surface, used the “ToSubD” command, copied this surface and moved it to the bottom of the extrusion and then tried to join the three open subD s. What happened next was that all the surfaces disappeared. I noticed that this only happened when “SubDJoinedEdges=smooth” and not “SubDJoinedEdges=Crease”. Pretty strange huh?

Thank you so much for posting these tutorials. I was just browsing through the news feed, exploring new updates in Rhino, tutorials,etc. and stumbled upon this. Thanks a ton!!:+1::+1:

use the tab button to alternate between box and smooth representation of the SubD surface

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When drawing sub-D face by face, how do you make the object correctly welded?
When I type join, it seems to joint object, but it still have sharp creases.

It seems automatically adding creases, is it possible to avoid this?

I tried drawing subd faces while appending faces, but I need to do these little step:
1 Draw subD face 2. draw 3 points 3. click append option 4. select sub.
Repeat.

I wish there could an option, to select the sub-d object, then draw faces that are always appended to sub-d. instead of going through 4 steps every time. The tab function is great.

Hi, here are two processes you may benefit from:

  1. Use ‘Stitch’ to weld vertices together when building face by face.

  2. After creating a single SubD face use Shift and Control to select an edge. Once selected drag the edge and press control to create new appended faces