Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

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DanielC
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Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby DanielC » Mon May 30, 2016 12:47 am

Hello,

I am new to FreeCAD and I love the "constraints" feature that you get inside a sketch. I find that constraints make a lot of sense to me and I'm wondering why I cannot use them in draft mode. In fact, I don't even understand why FreeCAD makes a distinction between sketches and drafts and seemingly cripples each one in a different way. From my naive point of view, it seems like there should be one workbench to draw in 2D, which should include constraints, and those 2D drawings should be usable for everything FreeCAD uses sketches for. As far as I can tell (again, I'm new) it seems like a draft can be used in the same ways as a sketch; but the draft is harder to draw because you cannot use constraints.
DeepSOIC
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby DeepSOIC » Mon May 30, 2016 9:23 am

Hi!
Draft and Sketch are very very different code-wise. They are even written in different programming languages (Draft in Python, Sketcher in C++).

And I can see any sensible way of merging sketcher and draft even from user point of view. Well, apart from adding BSpline/Bezier curve support to sketcher. As for that, no one seems to be brave enough to start coding B-Splines in sketcher.
ickby
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby ickby » Mon May 30, 2016 9:56 am

DanielC wrote:Hello,

I am new to FreeCAD and I love the "constraints" feature that you get inside a sketch. I find that constraints make a lot of sense to me and I'm wondering why I cannot use them in draft mode. In fact, I don't even understand why FreeCAD makes a distinction between sketches and drafts and seemingly cripples each one in a different way.
There is a historic reason for both existing parallel, draft was coded earlier, but it is not the only reason.
From my naive point of view, it seems like there should be one workbench to draw in 2D, which should include constraints, and those 2D drawings should be usable for everything FreeCAD uses sketches for. As far as I can tell (again, I'm new) it seems like a draft can be used in the same ways as a sketch; but the draft is harder to draw because you cannot use constraints.
But what about the people that don't like constraints and want to draft more manual? We also hear from time to time complaints about sketches and constraints being annoying :)

Personally I use both, dependend on my use cases. And I think that is hte best way of looking at them: different toolset to achieve the same result.
DanielC
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby DanielC » Mon May 30, 2016 10:25 am

ickby wrote: But what about the people that don't like constraints and want to draft more manual? We also hear from time to time complaints about sketches and constraints being annoying :)
I don't understand that response. If you don't like constraints, don't use them. To me this feels like if I said "FreeCAD should let me draw squares" and you replied "what about people who don't want to draw squares?". Is there a reason why it is impossible to choose whether you want to use constraints or not? Have I missed something?
ickby wrote: Personally I use both, dependend on my use cases. And I think that is hte best way of looking at them: different toolset to achieve the same result.
But they DON'T achieve the same result. Or at least, I haven't figured out how. As far as I can figure out, sketches are only used when you want to modify a 3D drawing. As far as I can figure out, you cannot use sketches if you want to make a 2D drawing, the way you can with drafts.

On a related question: How do I get dimensions on a draft? That comes out naturally with sketches. I guess there must be a way to do it with a draft, but I can't figure it out.
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yorik
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby yorik » Mon May 30, 2016 1:28 pm

One important thing for me is missing in setches, which makes me use Draft most of the time, is the snapping stuff. In construction you work a lot with imported 2D data (plans of existing buildings, etc), so you snap a lot when creating new objects.

I always have in the back of my mind the idea to recode the entire snapping interface of Draft in C++ to make it faster and available to other workbenches too, but I lacked courage so far ;)
DeepSOIC
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby DeepSOIC » Mon May 30, 2016 1:31 pm

yorik wrote:One important thing for me is missing in setches, which makes me use Draft most of the time, is the snapping stuff. In construction you work a lot with imported 2D data (plans of existing buildings, etc), so you snap a lot when creating new objects.
In 0.17, you should be able to link to imported geometry as external geometry in sketcher!
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yorik
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby yorik » Mon May 30, 2016 8:30 pm

DeepSOIC wrote:In 0.17, you should be able to link to imported geometry as external geometry in sketcher!
It looks like I still only explored a very small part of all the new stuff ;)
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby julianfoad » Wed Jun 01, 2016 10:03 pm

DanielC wrote:... I don't even understand why FreeCAD makes a distinction between sketches and drafts and seemingly cripples each one in a different way. From my naive point of view, it seems like there should be one workbench to draw in 2D, which should include constraints, and those 2D drawings should be usable for everything FreeCAD uses sketches for. As far as I can tell (again, I'm new) it seems like a draft can be used in the same ways as a sketch; but the draft is harder to draw because you cannot use constraints.
I feel the same. Having two separate and different sets of tools for 2D drawing doesn't make sense from a usability point of view. I see a better future in which there is a single set of drawing tools and constraints can be applied anywhere in a 2D plane.

I have some ideas about how this could work well. I wonder if anyone else does? Where's the best place to discuss and record these sorts of longer-term design goals? I'd love to be able to come here and read about people's plans and ambitions for the future of FreeCAD, like the way the FreeCAD online help page called "Arch Concept" describes the goals of the Arch module. The http://www.freecadweb.org/wiki/index.ph ... Program.21 page says something about "things are not planned ahead" but I'm sure that doesn't mean nobody has any idea what they want at all :-)
DanielC
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby DanielC » Sat Jun 04, 2016 12:24 am

You guys know more about 2D drawing than I do. If you wanted to somehow merge "Sketch" and "Draft" into a single 2D drawing tool, what do you think it should look like? Alternatively, is there a reason why merging sketches and drafts would be fundamentally a bad idea?


What I like about drafts:

- Constraints!
- The way you move and resize objects. It just feels easy and natural.
- Trim edge.
- Draw on a face of a 3D object!

What I like about drafts:

- Splines and Bezier curves!
- The snap feature is nice.

What I dislike about drafts:

- I really don't like the way you move and resize objects. I find it very awkward.


In principle, if sketcher had b-splines, Bezier curves, and the snap feature, would there be any need for draft? Or is there really a fundamental reason why FreeCAD really must have the two?
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Re: Why have bot "sketches" and "drafts" / Why can't I use constraints in drafts?

Postby cox » Sat Jun 04, 2016 7:10 am

One thing about Draft that I can not see Sketcher do as easily is 3D drafting, making geometry freely in 3D space, augmenting existing geometry with lines on multiple planes for using Part:Advanced Utility to make shapes.

I mean It could be done, but might not be as effective, creating (in worst case) etc. one line for each sketch seams a bit excessive to me.
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