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Certification Early Visibility Program- Calling all Onshape Users!

Onshape has reached the testing stage of a professional certification exam. We are looking for a limited number of volunteers to “test” the test. Note, the exam is still subject to change before release. The exam evaluates a user's ability in several different core Onshape topics including part modeling, assembly modeling, and data management techniques.

If you take the exam and pass, you will receive a certificate, when the exam is released. If you take the exam and do not pass, you will be eligible to retake the exam at no charge when it is officially released sometime in the next few months. The exam is open to all users regardless of subscription type.

Applications are due by Sept 1.

Applicants will be admitted mostly on a first come, first serve basis although there will be some exceptions to diversify the applicant pool (different plan types, different geographies, etc.). The exam is free for the users in this EVP-program. In exchange, the requirements for admission are:

Agreement to fill out a short survey regarding your experience following the exam
Ability to take the exam within 1 week of being notified that you are selected
The exam requires to be taken in 1 sitting, and can be as long as 2.5 hours (most users who have attempted it have taken between 1.5-2.5 hours to complete)

There are a limited number of testers required. So it is possible that even if you apply, you will not be invited to take the exam or you will be held back to take the exam at a later date. You will be informed of your status and your test taking window within a week of your application.

To apply to be part of this EVP program please fill out the following form

KatieHuffman

Re: Arc causing sketch to be overdefined - how?!?

tom_auger said:

MBartlett21 said:

If you delete one of the 1.5mm dimensions, it should work then.\
Thanks for your suggestion!

But those circles need to be that dimension as that measurement is derived from a real-world measurement. Does that make sense?

@tom_auger

If you delete one of the controlling dimensions, then make the two 1.5mm circles equal, it should then work fine without being over-defined.

MBartlett21

Curvature explained for normal people (video with animations)

It took me a while to finally "get" the difference between tangent and curvature continuity, so I made a video that explains exactly what curvature continuity is in an intuitive way without using any math.

Curvature continuity is all over the place in Onshape and CAD in general, but it can be tricky to understand and many of the explanations I've heard either lack specificity ("well, curvature is more smooth"), or jump straight to talking about calculus ("curvature means the first and second derivatives are equal, duh" 🤓 ). Neither explanation really gets at the intuition of it. Let me know what you think!

https://www.youtube.com/watch?v=X714INhNYL0&feature=youtu.be

EvanReese

Re: Arc causing sketch to be overdefined - how?!?

@tom_auger

In the first GIF, notice the way YOU sketched the arc and circle. As I moved my finger DIAGONALLY, the two center points stayed aligned vertically. So even though I had suppressed inferencing, the two points still stayed aligned vertically

In the second GIF I did not bother to suppress inferencing.

The two points were aligned vertically, so all I had to do was punch in a vertical dimension — between the two points — of ZERO — in order to make the two points coincident.

Look at the latter part of the second GIF, where it shows the X, Y & Z coordinates for the centers of the arc and circle. Notice they are exactly the same

steve_shubin

Re: Arc causing sketch to be overdefined - how?!?

@tom_auger - I think the thing to remember here is not that the geometry is invalid, rather as you say, its's overdefined. And because it's overdefined, the software throws an error.

The sketch solver has to solve a system of equations. So for example, we have equations:

x+1=2
y+x=5
x+2=3

We can easily figure out that x=1 and y=4. The third equation isn't incorrect, its just not needed (and the system of equations is over-defined).

Similarly, in your sketch, you could look at the one of the vertical edges. It's position (1.75 inches from the center of the large circle) is defined by the size of your construction circles and the sketch is happy. However, when you add the last arc and constrain the center of the arc on the horizontal line and tangent to either of the vertical lines, it has to also be tangent to the other vertical line. Therefore they two vertical lines have to be symmetric and each 1.75 inches from the center of the large circle (creating a duplicate constraint that makes Onshape unhappy).

So, while all the dimensions currently add up, you're essentially providing too much information. There are probably many different constraints you could delete to solve the issue. But, I think what you're looking for is something that would also retain design intent (deleting one of the small circle tangent constraints would allow the sketch to solve, but that might not reflect design intent).

I deleted the large arc and re-drew it using the 3-point arc tool. When I re-drew it, I allowed it to auto-inference that I wanted the center of the arc at the center of the large construction circle. All seems to be happy with this method.

https://cad.onshape.com/documents/1036e67ad80fbb5bff9b7631/w/910b633452369b807538751f/e/01b67eec6b0226517cc0c871

tim_hess427

Re: Variables and driver/ driven dimensions

No way to extract it to a table, but they do create variables.

So you can do a lot with them once they are created, including importing them into other part studios/documents

john_mcclary

Re: Variables and driver/ driven dimensions

You can use 'equal' constraints, but they will measure the length of the object relative to the sketch plane you are projecting to. So only works if they are on the same parallel plane.

Unfortunately there is no built-in ability to 'link' dimensions.

Measure value is a good feature to use here
https://cad.onshape.com/documents/77baa8153589a7fc5f289829/v/ceb4a03e4ac77173bf6d0074/e/181cb871f3008e6b885df46a

john_mcclary

Re: Why has my Forums view switched to German and how do I change it?

There is a switch in the very bottom left corner
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NeilCooke

Re: Why is not possible to shell this part ?

Seems like you have some accidental sliver faces that are probably causing issues.

EvanReese

Re: Split and recombine surface?

@tom_auger

Thanks for sharing Tom. Do you have a link to the Document so we can take a closer look?

Whenever working with patterns or parts with symmetry, try to produce only one feature and pattern that feature afterwards. In this example, you could probably get away with just a single tooth that is patterned after all features have been created.

John_P_Desilets