constraining a sketch

[conjured2018]

My designs are free form sketches. I then extrude, sweep, loft to get components I want. I have never constrained a sketch. am I missing something?

Part attached is a free form made with 3 point arc, splines, extruded to .75 and then I use splines to set curves and cut with extrude. back of my head says model this with forms yet I am not good enuf using them.

I also will stack the parts and then cut out a curve using sweep.

JR

[TrippyLighting]

You are missing the very basics of parametric design! I don't even know where o start ...

[jeff_strater]

This is somewhat a matter of opinion.  It is definitely a best practice to fully constrain your sketches, but that practice becomes important if you plan to go back and edit your design parametrically (e.g. change the overall size using a parameter).  Fully constrained sketches behave much better under edit that under-constrained sketches.  But, if you are OK with that potential danger, or don't plan to edit the design parametrically, there might not be a need to fully constrain your sketch.  Fully constraining splines can be a pain.

The design you shared here does not seem to have any sketches in it, however...

[TrippyLighting]

I would have to disagree, yet I don't always fully dimension and constrain my sketches either.

However, there is a major difference between my skill level the OPs.

I know very precisely what I am doing and what I can get away with. 

The OP on the other hand should first learn why and how to properly drive a parametric modeling software, before venturing to more advanced topics.

[g-andresen]

Hi,

If you show a picture of a real existing object, there would be an approach for target-oriented hints.

günther

[conjured2018]

here is a sketch fellas. Now I derive the part. I have another file where all edits are made on part. when I edit and save the little yellow thing at top left is on. I click it and all changes go to derived part.

Is this not parametric modelling?

and please show me how to constrain a free form. thank u JR

what is an OP?

[g-andresen]

Hi,

1. OP points to the person who opened the thread > Opener .

2. The sketch consists of 3 splines without any definition.
References to further features such as extrusions ... are missing, as is the image of a real object.

On this basis, one can neither give hints about the object nor basically about the parametrics.

günther

[TrippyLighting]

OP stands for "original poster".

You call your sketch "free form". I call it a formless blob 😉

If you can share an image of what you want to design that would be helpful. Then we can recommend better workflows, starting with a proper sketch. 

[conjured2018]

this sketch can not be constrained?

[g-andresen]

Hi,

If you want your sketch to be "fully determined", the coordinates of all control points as well as the length and slope of their tangents must be defined.

Like this :

günther

[TrippyLighting]

You have not provided the information and/or answers you have been asked for. Please don't reply to this post with another question and provide what u have been asked for!

While you're at it, also do this in the other threads you have started.

That sketch can be constrained. As it is right now, that is a lot of work for possibly diminishing returns. The question is whether you are actually using the correct sketch tools. Just because you use free forms, does not mean that you have to use splines, nor does it mean that the splines you are using have to have that many spline points.

Please provide an image of what you want to design.

[conjured2018]

attached is full workflow for one part. Notice no constraints. thank  you

[TrippyLighting]

And what does that represent ?