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Sketches not fully defined and I... admittedly don't understand constraints yet.
christopher_leffel
Member Posts: 5 ✭
Okay, I'm at a loss for what I'm doing wrong here in that my sketches aren't fully defined. I get that it has something to do with constraints and possibly mate connectors, but I have no idea what I have to do to fix it. I see all kinds of discussions on WHY parts need to be fully defined, etc., but I'm finding exactly nothing telling me HOW to fix it. A clear explanation of what steps will actually resolve the error would be much appreciated!
0
Answers
Have you done any of the fundamental training from learn.onshape.com? You might find it helpful to learn what constraints do what and how to adjust them.
so when you define the length, width and radii of your geometry, the shape is fully defined. but the position is not!
the lower line is black and so it's probably constrained vertically, but the end vertices are blue so they can probably move horizontally still.
so you may be one (horizontal) dimension/constraint away from fully defining your sketch…
No.
I am coming at this from rusty experience with AutoDesk, 3dsMax, Maya and the like.
If someone could even just get me pointed in the right direction to what/where I need to click in the interface - I honestly don't have time to go through a bunch of random courses to finally find the one piece of information or series of steps I need. I tried reading forum posts, tried finding a relevant video (though I'd really prefer text)… but… even a link just to the right training for the question at hand…
'Anchor' your sketch by intersecting a point in it to the origin or by dimensioning a point in the sketch to the origin. In the future, consider starting the first element in a sketch at the origin. - Scotty
simply searching for fundamentals or constraints at that website would likely yield you an answer that would pay dividends down the road. if you really want to shortcut it and the the blue dot is a real hindrance…. just select everything and click on the fix constraint. 90% of the time this questions comes up its related to Scotty's comment, you haven't told the program where you want the sketch located in relation to existing geometry.
I'm unable to determine why this is not fully defined. Everything has a constraint or a dimension, per the tutorial I'm following, but it's no go. What's the element I'm missing?
The angled line with the 35 dimension is not aligned horizontally or at a specific angle. It's also not going through the center of the circles. in other words, there's not a lot really constraining the size of the whole thing.
Simon Gatrall | Product Development Specialist | Open For Work
It looks like you've not constrained anything "vertically" to existing geometry/elements.
Maybe a tangent constraint would help
@bruce_price ,
Just grab a corner (or anything blue) and start dragging slowly with the mouse and see what moves, it should help understand what is "unconstrained".
Off the bat, I can see you're missing a dimension for either the large circle or the small circle (your pick)
+1 this is the way to go
The BEST way to determine whether or not you've fully constrained a sketch (besides blue vs black/white) is to drag some of the blue points/lines around. Do they change in an unexpected way?
Ramon Yip | glassboard.com
I like the 'cookie-cutter analogy' when it comes to sketch constraints. An un-dimensioned, un-constrained sketch is like a cookie-cutter made out of some sort of stretchy rubber; unpredictable and therefore useless.
CADNurd's Linktree - find me everywhere else - https://linktr.ee/Liam.G
I thought that if I constrained the circles to the rectangle parts, that would constrain the circles. Fix the suggestions, and I'm now I'm fully constrained. Thanks for the quick assist. Now it's on to the next stage.
Here's another constraint issue
Everything seems to have a measurement but ?
Blue fillets are not tangent - add a tangent constraint
Here I am again, can't figure out why it's not fully defined.
Again with the constraints and believing I've done everything, but I still can't fully define it. Frustrated with constraints
!!
Sorry to hear you're frustrated. Trust me, in time it will click and it will become second nature. Until then, we're happy to help.
As before, the answer is still to touch everything one at a time and drag it.
What I can see right now is your 2.25 line isn't set to vertical
Your 1.063 line is not locked in horizontal or perpendicular to the 2.25 line (your choice)
The 2.625 has the same issue as the 1.063 line.
You may need to put a dim on the spline control arms as well. But I think making the top and bottom lines horizontal will lock it in.
It may help for you to break it down into entity type and what it takes to fully define them. So do you know what it takes to fully define a point or a line or a circle, etc? If you know that it might get you over the hurdle of a full sketch being fully defined.
john_mcclary, that worked for the bottom line, but the top and splined are still not defined. Added dim to the curve and added a horizontal, but it is still not defined. Thanks!
MDesign I did the intro tutorial, but still not comfortable. I will look into it further. Thanks for the suggestion.
It's hard to see it without dragging it. I sketched up the situation I assume you are in. As you can see, dragging things around at all means they are not defined.
So drag something blue, see how it responds, add a dimension or constraint that makes sense for the design intent. And repeat until it's all black
So ask yourself what is required to define a single point? An x y and z relative to another point that is not in the sketch you are working on. The sketch plane is your z. so that's given constraint. now you need a constraint for x and y. That can be 2 dimensions or 2 alignments or a combination of the two.
Hopefully that makes sense. Moving on to a line. now you have 2 points to constrain and a line connecting them.. rember all z's are contrained by the sketch plane. and the line needs to know where one of the endpoints is relative to something not in the sketch. So using either 2 dims or 2 contrraints or a combo to define one endpoint. then you need an angle and length to constrain the other endpoint. pick your poison on which combo of dims and constraints you want to use for that.
All your doing is saying "hey OnShape. This is where I want my sketch entities to exist in the world and you can't move them from these positions unless I say so. So I'm telling you where they are located, and how big they are."
update: got everything defined but for the spline. Still unsure about why. I find that the endpoints weren't linked to the two horizontal lines, so I did a coincident constraint on each, but still blue.
do you have a link? It's impossible to tell from screenshots alone. Again, you need to grab the non-black sketch entities and drag them around. Then restrict their motion with constraints or dimensions in a way that makes sense for your shape.
John_McClary New so hope this is what you're asking for
https://cad.onshape.com/documents/b88da28dfe79d45b0e22e7ed/w/a1f3c049f2ad552b533282fb/e/c09a957e912b60a84196aaba?renderMode=0&uiState=69681fc999ef530440e33c58
all of these points are open to interpretation on where they should be located.. I would zoom in on top left and set them coincident with each other. I'd delete the spline you have now and put a new two point spline in and drag the magintude controls to get the shape you want and add the spline length dimension and magintude dimensions and change the bottom dimension to driving.
https://cad.onshape.com/documents/254fb421d6e68b7ea3543095/w/708e0188e7d913bbbe984bc9/e/cf5b752d00d369ebe1dceb44
there were a couple of stray objects floating around. you may have been attaching to those by accident.
window selecting and deleting helps purge that stuff out, just window select from left to right to get a blue window. This only selects objects fully within the blue window. So, you don't end up deleting the geometry you DO want.
Here is a video of my walking through solving this sketch with some commentary.
There was defiantly no way we would have solved this without touching the sketch and feeling our way. Thank you for the link
Didn't know about Drive lines, did as suggested. Replaced the spline, added dimensions, and somehow lost defining on the upper line. Spline still not defined. I have trouble finding information or tutorials on defining splines that aren't math-heavy or overly explanatory. Any suggestions on that would be helpful. Splines are stumping me.
https://cad.onshape.com/documents/b88da28dfe79d45b0e22e7ed/w/a1f3c049f2ad552b533282fb/e/c09a957e912b60a84196aaba?renderMode=0&uiState=696955a77ec5b481ed63a1a0
The gif I showed was showing some abnormal glitches. Don't get discouraged, that was worth asking for help
Thanks for the encouragement. As a newcomer, I'm expecting a steep learning curve. This is my first project post-intro tutorial. This is a profile I plan to rotate and print to create a plaster mold for my ceramic practice.
I did a version with only lines and got it fully defined, then tried with a spline and can't get it to fully define. There's something I'm missing in defining splines.
https://cad.onshape.com/documents/df3681e18bca8a92816c8a07/w/f1d8ae2708126bd67ecdf0fe/e/830fdf46a768ea4ce1f9c8c2?renderMode=0&uiState=696a3c61b369895216e80cd5