Newbie trying to do constrained design changes

Newbie here. I’m trying a very simple design where I make a simple sketch, constrain it, then extrude it, make a couple chamfers to the edges, go back to the sketch and change something. The 3D model seems to become “detached” from the sketch instead of adjusting to match it.

How to recreate:

  1. Sketch a circle, constrain its diameter to 3cm.
  2. Sketch another, say 5cm.
  3. Constrain the circles do they’re concentric.
  4. Sketch a line from the bottom of the smaller circle to the bottom of the larger.
  5. Constrain the line so it’s 2cm.

Now the larger circle will always be concentric to the smaller and always 2cm larger. Perfect.

  1. Rotate the viewport, select the “donut” space between the two circles and extrude say 8cm.

Now I have an 8cm long tube with an inner diameter of 3cm and an outer diameter of 5cm. I can play with the edges to make them rounded. Works great.

  1. Go back to the sketch (double tap the top of the cylinder)
  2. Tap the smaller circle and change the diameter to 3cm.

What is expected: the donut changes so it’s got an i.d. of 3cm and o.d. of 5cm, with the same chamfers it had a moment ago.

What happens: the tube doesn’t change at all, but the sketch does.

I’m absolutely sure I’m doing something wrong. What is it?

Instead of adjusting the sketch diameter, use the Offset Face tool to adjust the object itself. In your case, select the inner wall and offset it 0.5mm.

Hi!

Nothing’s wrong.

Shapr3D is a direct modeling tool, meaning there is no connection between the sketches, and the bodies made from them once they are created. After you create the body, you can directly modify it.

It has it’s pros and cons of course, and may take a bit of time to adjust if you are coming from a history based tool.

I understand that it’s a direct modeller, and I see awesome technical models. What I don’t see is how I can constrain the models so that I can directly manipulate them and maintain constraints.

Is there a demo/tutorial that shows how to handle this kind of problem? I’m all for changing my approach, but at present it doesn’t look like you can do constrained 3D modeling with THIS direct modeller. Is that a fair statement?

Yes, currently there are no constraints for the 3D models available.

You can move bodies into folders, that way when you select the folder, all bodies will be selected too, so some actions/tools are available to be used on all of them (e.g move them together). On mac, area selection is also available, and it will come to iPad soon, which may help a bit.

Ok; this helps me understand.

It’s not just that that direct modelling requires a different mentality (manipulate the model not the sketch), but presently the lack of constraints on models makes it impossible to manipulate the models while maintaining relationships between features (for the most part, you mentioned there are some basic group features that can emulate constraints).

I’ve also seen that a basic history feature was “top of list” for future features. For me, these are the two features that are keeping me from buying the pro licence. I’m very eagerly awaiting this, there are no other modellers for iPad and OSX that also don’t lock you into cloud blah-blah.

Thank you for clarifying this for me, I could not figure out if it was just my inability to see how to constrain models/think differently (direct vs parametric) or if Shapr3D was presently capable of doing it. I have no doubt it will, and I’m super excited for that day!

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On it! Prototyping at the moment, but it will be awesome. We will have a most amazing design history implementation in the industry. We are very excited about it.

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