Why do sketches separate from objects?

I have been trying to move away from my desktop 3D, (which is mainly FreeCAD but I’ve also used SolidWorks) into Shapr3D but honestly there are certain things that seem a bit strange.

In most 3D parametric CADs the sketch is like a mode and it’s always tied to the 3D object (i.e. you switch between Sketch Mode and Object Mode) But in Shapr3D it seems that once the object is extruded then it is separated from the original sketch. For example, if you move the object, the original sketch stays in the original place. Is this “feature” and if so, what is the reasoning behind this behaviour? Or is this a limitation?

What happens if you just erase the original sketch? Is this safe? How do you turn off the object mode to effectively cleanup the sketches that are left everywhere? Seems too weird for me.

i mean this software seems fine to quickly prototype something but once you start getting into editing stuff it seems a bit quirky, or I am simply not understanding it’s philosophy.

TIA for any comments or explanations on th philosophy of the sketching engine and editing shapes and sketches after you have extruded them.


Because Shapr3D is a direct modeling tool, and not a history based tool like SolidWorks. This has many benefits, especially in conceptual design, but can be confusing for somebody who is used to history based tools. It requires a different way of thinking, but it’s not less powerful.

Here is a good description about direct modeling: https://www.concurrent-engineering.co.uk/blog/blog/bid/93709/what-cad-users-need-to-know-about-direct-modeling

Thanks for both answers, this is very helpful. Do you have a document or tutorial or a “ how to transition from historical modelling to direct modelling”. I am sure I am not the only user perplexed by some of the behaviour.

I have fallen victim to dependency hell in complex models in traditional CADs where editing an ancestor sketch will break the whole model downstream. If direct modelling addresses this, this would be a compelling reason to change one’s paradigm.

But how exactly does direct modelling address this? E.g. are sketches disposable in direct modelling? If so, is there an easy way to clean them up? Once the shape is extruded then you forget about the sketch altogether? If so, shouldn’t they just disappear ? I haven’t found a way to even turn sketches off and viewing them is very annoying.

Unfortunately we don’t have a document about transitioning from history based to direct modeing yet :frowning:

Yes, sketches are disposable in direct modeling. Once you extruded/lofted/revolved etc. the profile, the sketch has no connection with the body.

The idea behind history based modeling, is that the modeler will store a series of modeling steps instead of the geometry, and you can edit that history. Unfortunately this is not as robust as it should be, often leading to all kind of problems (broken feature history, etc.)

Direct modeling is addressing this issue by allowing the user to directly edit the geometry. Eg. in a history based system to modify the height of an extrusion, you have to go to the extrusion step, then set the height of an extrusion. In direct modeling, you can simply push or pull the face to move it, and the underlying magical algorithms will just rebuild the body.

Thanks, I think I can picture the benefits and starting to get it.

Is there an easy way to cleanup and delete sketches that are left all over the place? Or at least an easy to hide them? Sketches may be useful for spec documents but there should be a way to move them out of the way and then display or export them for documenting purposes.

Is this what layers are for? Is there a workflow to keep sketches organized and get them out of the way of direct modelling after the part is extruded?

Yes, in the groups menu you can easily delete them:

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I attended the first webinar and it was really amazing!! It clearly demonstrated what direct modeling is all about and gives you some good workflow ideas and best practices when using Shapr3D.

I finally understood some of the key philosophical differences with a traditional parametric 3D CAD.
Great job and a big Kudos for Claas Kuhnen!