I still don't get sketching right....

[Helmi74]

Hey guys,

after quite a while with Fusion360 now i still seem to have trouble to fully use the features sketching offers me. As i somehow know this should work i can't seem to get stuff right. What's the most secret to me is getting constraints right (and a bit dimensions too).

While i know things maybe hard to explain without an example i have one which is probably simple for those who know how it works already.

Here's a screenshot:

I extracted that from a project and put it into a single document to be able to use history based modelling and parameters as i want to play around with different settings to get the part there where i want it to be. I've sketched that ugly colorful lines in there:

- yellow: distance between two circles which build a pair

- green: distance between the circles of a pair to the pair next to each

- red: diameter of circles

Now i want this to be as flexible as possible with paramters to play around varyiing the single values . Each pair must stay in an angle of 120° to it's neighbour pair. I don't care too much about the outline though it would be great to to play with the distance of the outline to the outer line of the circles.

Of course i know how to put all the values in parameters but i'm completely beaten when it comes to the angles and constraints.

Maybe someone of the team or any other more experienced users could give me hint or show in a short commented screencast how this could work.

Thanks for helping,

Frank

[TheCADWhisperer]

I am not certain of your design intent - but examine the attached file.

Change the Ø100mm circle to any other size (double click on the dimension).

Note that the other dimensions are a function of this dimension.

Note that there are geometric constraints defining the relationships between all sketch geometry.

Hmmm, this is interesting.

Sometimes when I make a large change to the Ø100 (say to 1000) I get an overconstrained error.  Not sure if I made a mistake in there somewhere.

When I go up in smaller increments I don't get the error.

[Helmi74]

Hey thanks a lot.

Maybe i haven't been clear enough in my descriptions. I know the basics of dimensions and parameters/variables of course but expecially for the case above where relations are a bit more complicated and multiple releations need to be taken into account and different positions need to be fixed or variable to keep the basic geometry - that's it what i can't get fixed.

apart from that if i change d7 in your drawing all i get is an error due to overconstraints.

Thanks anyway for helping! Highly appreciated.

[Helmi74 · Accepted solution]

Ok,

looks like i got that managed myself - somehow i seem to have had some knots in my brain windings 🙂 I've watched the old screencast from Nathan here (thanks again, stuff like this is really valuable) and that helped me as a kickstarter. I found the right way to use different constraints to get it managed. To make this thread even a little bit valuable i will add the file though it doesn't really explain how things work - i should do a screencast next time for maybe other searching for that stuff later.

To change any of the key values go to the parameters section and edit the user params - don't edit any of the dimension values directly.

[Helmi74]

I found out there's even a better/smarter way then using thousands of parameters. I renamed some values, deleted some user paramters and fell in love a bit with Constraints, here's a newer version that also solves the border thing and works with equal contraints. This way only one user paramter is left, everything else can directly be changed in the sketch itself with by changing the few dimensions that are still there.

I still miss a better user interface for parameters - i think this window that always needs to be closed and reopened is not a good/hand UI to work with paramters. We already had this discussion early when parameters were released.