Curvature explained for normal people (video with animations)

Evan_Reese

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

michael3424

Thanks - that explanation and examples were helpful.  I'd like to see more of these covering other Onshape topics.

tim_hess427

@Evan_Reese -this was great! If you ever do an update to the video - I was thinking it would have been neat to the connect the curvature combs back to the car/steering wheel example.

The height of the comb would be analogous to the angle of the steering wheel, would it not?

Evan_Reese

michael3424 said:

Thanks - that explanation and examples were helpful.  I'd like to see more of these covering other Onshape topics.

Thanks! I plan to make some. What topics in particular?

Evan_Reese

tim_hess427 said:

@Evan_Reese -this was great! If you ever do an update to the video - I was thinking it would have been neat to the connect the curvature combs back to the car/steering wheel example.

The height of the comb would be analogous to the angle of the steering wheel, would it not?

You're exactly right. The length of the comb would indicate how far the steering wheel is turned at that point on the curve. Mentioning that would have helped everything tie in a bit better. Updating means I'd have to delete the video and re-upload, so I'll leave it alone and put my effort toward a new video instead. What other subjects would you like to see a video about?

bruce_williams

@Evan_Reese
Excellent!  I did not know what I did not know.  Your explanation and examples are really helpful.  The car steering wheel is brilliant.  I am going to make this a 'must watch' for our team.  Thanks so much for making & sharing!

Other topic suggestions - tips & tricks on splines (2d & 3d), surface editing (repair, extend/trim, blend, smooth), feature script for dummies, icon graphics

michael3424

Evan_Reese said:

Thanks! I plan to make some. What topics in particular?

Something on pierce and how it should be used would be nice, for me at least.

Evan_Reese

bruce_williams said:

@Evan_Reese
Excellent!  I did not know what I did not know.  Your explanation and examples are really helpful.  The car steering wheel is brilliant.  I am going to make this a 'must watch' for our team.  Thanks so much for making & sharing!

Other topic suggestions - tips & tricks on splines (2d & 3d), surface editing (repair, extend/trim, blend, smooth), feature script for dummies, icon graphics

Thanks for the kind words, and even more for the suggested topics. I'll consider what I could teach about feature script. I'm thinking that "for beginners, by a beginner" could actually kind of work. (I may be more qualified for that than anyone at Onshape, haha). I've never done any other code, so I can still remember the things that tripped me up that are too second-nature to the pros to even think to mention.

Evan_Reese

michael3424 said:

Evan_Reese said:

Thanks! I plan to make some. What topics in particular?

Something on pierce and how it should be used would be nice, for me at least.

good one. Probably too small for a standalone video, but would fit well into a "sketching tips" video or something

tim_hess427

I'd second the splines and surfacing. I think I have a good understanding of the "tools" individually, but I don't feel like I have good modeling strategies or workflows when using these tools. It still feels like I'm hacking things together.

Evan_Reese

@tim_hess427
good feedback. I love surfacing stuff. In my opinion, Onshape still has a decent bit of work to do on their surfacing tools for me to do the work I used to do in Solidworks (this is one of the only things that makes me think wistfully about the Solidworks days). It's definitely still possible to do good work in Onshape though, but it can take a bit more forethought, and more features. I will be thinking of some good examples.

Onshape, if you're seeing this, my biggest priorities in surfacing are:

1. Loft - not needing the same curve count, and the ability to synchronize the loft, preferably from inside the feature. this one thing outweighs any other surfacing improvements to me 10:1.
2. sketch spline tools - the curvature constraint fails for me in situations that I think should be able to solve. I'd also really love a control point spline, similar to Rhino. Surfaces can only be as good as the curves that make them, so this really matters to me.

Ste_Wilson

Wow...Finally got around to watching this....mind blown.  I'd never even thought about this, let alone didn't understand it!  Great video!

Konstantin_Sh

Evan_Reese said:

1. Loft - not needing the same curve count, and the ability to synchronize the loft, preferably from inside the feature. this one thing outweighs any other surfacing improvements to me 10:1.

Agree with this, I think Loft actually should map profiles proportionally to their length by default, but also there should be ability to select more then one pair of matching vertices for cases when proportional matching is unwanted.

Evan_Reese

stephen_wilson554 said:

Wow...Finally got around to watching this....mind blown.  I'd never even thought about this, let alone didn't understand it!  Great video!

haha, now you've hopefully done both! 

Evan_Reese

michael3424 said:

Evan_Reese said:

Thanks! I plan to make some. What topics in particular?

Something on pierce and how it should be used would be nice, for me at least.

I recorded this clip as part of a larger "Sketch Tips" video I'm working on, but felt it didn't fit the theme as well as I wanted and the video is getting pretty long as is, so I decided to cut it. Here's a 1-minute explanation of pierce vs coincident: https://www.loom.com/share/86c27b6dae794f41a9669991bc3b1e4e

michael3424

Evan_Reese said:

I recorded this clip as part of a larger "Sketch Tips" video I'm working on, but felt it didn't fit the theme as well as I wanted and the video is getting pretty long as is, so I decided to cut it. Here's a 1-minute explanation of pierce vs coincident: https://www.loom.com/share/86c27b6dae794f41a9669991bc3b1e4e

Thanks - that was an excellent intro to the subject matter and I really appreciate your taking the time to produce it.