Procedural Torus Knots with Blender Geometry Nodes!

[@ash_weeks]

The cyclical spline issue seems to be fixed in Blender 4+ (maybe earlier versions too)

[@fuglsnef]

I love the way you set up the frames as placeholders for the variables, it made it really easy to follow!

[@JohnnyMatthews]

That helps me so much when I remember to do it!

[@tufjos0ra]

For anyone who is still wondering, to fix the curve to mesh twisting problem just add a set "spline type" node set to "NURBS" after the original curve circle. Thank you for the video!

[@ajcross7]

Johnny I know I already commented but I have to say again - this I think is legitimately one of the top 10 best blender tutorials on all of KZbin. Including everybody, all the big names, blenderguru and everybody. I wrestled to grock this lesson fully and it has been huge in influencing my thinking. Thank you

[@JohnnyMatthews]

That is high praise. You are too kind.

[@johnsmith56920]

I think Johnny is (or at least should be) one of the big names.

[@flavio8430]

Amazed on how you organized the math nodes -- thanks for sharing!

[@JohnnyMatthews]

My pleasure!

[@flavio8430]

@@JohnnyMatthews I must confess that I didn't understand why you used a Spline Parameter to generate φ... You said "anytime you see a value between 0 and 2*π you think a circle"... Why??

[@JohnnyMatthews]

Since we used a curve circle as our base object it is a single "spline" (one curve in a curve object) The spline parameter then evaluates along the length of that curve. If we were just making a circle then 2π would be the distance around the circle in radians. When you convert 2π to degrees, it is 360. The equation for the knot starts at 0 radians and goes up to 2π. It just happens that it loops around more than once like a circle. Hopefully that is not more confusing than the video.

[@flavio8430]

@@JohnnyMatthews Got it! My rusty math brain engines need some oil... :) Thanks for the help!

[@JohnnyMatthews]

Of course! Thanks for watching and interacting.

[@AhmedNassef]

This was surprisingly easy! Thanks for opening up doors for us, man..!

[@JohnnyMatthews]

You’re welcome! Hope you do something cool with it 😊

[@kes099]

Wonderful! Love how you laid out the math using nodes. This makes me believe that you will be able to build anything that has a mathematical formula and I really encourage you to tackle some more projects to share with the rest of us... suggestions: Newtonian telescope mirror, radar dish, optical elements of a camera lens, suspension bridge, molecules, solar system :)

[@sbusisomcebongwenya167]

WOW. Very informative tut. i have found m new favourite geonodes channel :)

[@ajcross7]

Johnny - what an excellent tutorial. You are becoming really superb with geo nodes. Thank you

[@JohnnyMatthews]

Thanks for the kind words! I’m glad it’s connecting with people!

[@zboy303]

Love watching your thought process in converting equations into useable GN.

[@JohnnyMatthews]

My thought process can be a scary thing 🤣

[@megasculptor4954]

That's real Python programming, yes, thank you. thank you . When I think of all the parametric representations of functions whose equations I know, I won't get bored at all. I have the impression of finding myself on Geo Gebra. blender is awesome. Johnny you are the best math teacher for blender!!!!!😁

[@JohnnyMatthews]

Thanks for the kind words.

[@deslomator]

Whoah! I happened to have a file opened where the merge by distance trick was really helpful, thank you!

[@JohnnyMatthews]

Nice!!!

[@megasculptor4954]

thank you Jonny, your videos are interesting, do not hesitate to explain things with mathematics, we are here to understand. you know there are few youtubeurs who do it. By explaining to us how things are done with math, we have everything because everything starts from math. I'm so happy to see your videos really thank you and I promise you that when my projects bear financial fruit I will not fail to support you. God bless you !

[@JohnnyMatthews]

I appreciate that! Thanks for watching and learning with me.

[@JohnnySix]

Love the attention to detail and the tidy node layouts so it's easy to follow what's happening at each step. BTW Learning it's pronounced "Fee" in Latin, but "Fy" in English blew my mind.

[@JohnnyMatthews]

I took Koine Greek in college and that's the way I was taught to say it, so it's always fee to me. :)

[@JohnnySix]

@@JohnnyMatthews whoops ! Yes, I meant greek not latin hahaha :D I thank Brakeys for the correct pronouncement of Ludum Dare .

[@qedqubit]

Thanks for taking us through the math part 😀 !

[@JohnnyMatthews]

Oh yeah, I figured the whole thing wouldn't make much sense without it!

[@duncanrudd348]

Superb - great explanation, thanks for sharing!

[@JohnnyMatthews]

My pleasure!

[@snakeyengel]

Incredible work, sir.

[@JohnnyMatthews]

Thank you kindly!

[@sparklecats-vk2gi]

Hi Johnny, When I do the fake user button and delete my node, and then switch to the new node and add the torusknot, it still doesn't appear in my viewport. Do you know why this could happen?

[@snakeyengel]

An axillary question, good sir: I made a nice animation using the Trim Curve node. It starts with 0:0 (Start 0.000, End 0.000), at the zenith is 0:1, then I collapse the start point to the end point and reverse everything and go from 0:1 to 1:1, and then it's loopable, with a nice camera rig and all that. EzPz. My question is, when I go from 0:0 to 0:1, with shade smooth turned off, the spline is rock solid and it does what you would expect. When it goes in complete reverse, i.e. the start point goes from 0 to 1 and the end point stays at 1, the spline wants to do a weird twisting kind of motion. It forced me to go shade smooth. Why would it do that? I thought if anyone would know, you would! Cheers!

[@nicolasherrbach3757]

It’s probably the normals being recalculated. Try to add a Set Curve Normal node with Z Up option.

[@BlendingEdge]

Btw, not sure what changed in latest Blender (4.0.2) but i don’t get the twisted artifact at the end... so no need to fix anything. torus knot curve based on circle + set position and curve to mesh with a circle as a profile works just fine.

[@grobknoblin5402]

This is super cool!!!!

[@JohnnyMatthews]

Glad you think so!

[@johnsmith56920]

Hi. Thanks for your tutorials. I am in the middle of something and it would go faster if I used a parametric equation like x = sin(u)cos(v). Usually the equation specifies 0

[@JohnnyMatthews]

It sounds like it unless there is another definition of u somewhere

[@johnsmith56920]

@@JohnnyMatthews Problem is I got no results so far with u being whatever I want 🙂

[@BlendingEdge]

Cool. though I wish GN had was a dedicated native node for this.

[@johnsmith56920]

I want to connect an ellipsoid with a hyperboloid so that the "upper" part is the top of the ellipsoid and the bottom is the hperboloid. I want to have a smooth junction (same normals at the junction). Any tip anyone?

[@kadabra8]

Бананова фігура🤤👍

[@davidbell6101]

good and useful!

[@JohnnyMatthews]

Glad you think so! I liked it a lot :)

[@davidbell6101]

@@JohnnyMatthews I really liked how you used nodes to represent the input before they were wired up ... that was very helpful

[@JohnnyMatthews]

Helps keep my brain on track!

[@PatrickHengartner]

Amazing tutorial, I followed it step by step and double and triple-checked the math set up, but somehow it comes out fucked up. I am using Blender 4.1

[@SteelBlueVision]

I still don't understand why there is no simple torus geometry node to this day.

[@palpytine]

Auto-upvote for using "tau"