Loft Curves Properly - Geometry Nodes in Blender 3.6

[@Erindale]

Lofting is one of the cornerstones of parametric modeling. What other topics do you want me to cover?

[@cgdoctor8241]

Procedural road modelling with intersections

[@gottagowork]

This setup, by Entagma using Houdini: New In Houdini 19.5 Pt.1: Tangent Fields (And a Bit of VEX) New In Houdini 19.5 Pt 2: Karma XPU Beta (MaterialX, Solaris) Have a think on it first, if treating tangent singularities via attribute smoothing is even possible. This does cross over to materials and anisotropic shading, which Cycles may handle differently. One bug (feature according to devs) is that UV driven tangents don't smooth across UV seam.

[@aarcharanya]

@@cgdoctor8241second that

[@aarcharanya]

Pls make a tutorial explaining the curve & mesh topology nodes.

[@yudakan]

@@aarcharanya yeah, tutorial on topology nodes is sparse and a bit hard to find. And maybe after that you can cover utilities → field nodes?

[@ilirbeqiri]

Thank you for sharing this. Very thorough. I’ve got two suggestions though. 1- At 39:09 you’re right to use 2 Align to Euler nodes to properly orient the profile instances along the guide curve. But the proper way would be to align the Z axis to the Tangent direction of the guide curve and then align the resulting rotation vector to the Normal direction of the same guide curve. Leave the mode to Auto (that’s recommended by Blender in the manual). The order of these operations isn’t really important. There’s no risk of Gimbal lock. The alignments represent 2 consecutive transformations. This makes the orientation along the curve rock solid, no matter the guide shape. Also avoids the need to calculate which way is front. 2- At 23:08, the trick to split the edges of a single line mesh using a Duplicate Element in Edges mode is a very pleasant surprise, but instead of converting repeatedly from curve to mesh and back, a simple Subdivide Curve node could have sufficed. Again, thank you for sharing a detailed and unified way to loft curves. I’m bookmarking this to easily reference it later.

[@Moustafakhaled-c6q]

39:50 if you try to create a "bench path" that has a point up the Y-axis and you want the curves to follow you get weird rotation not exactly following the path, in which case you leave the align as is in this time code (first rotate around the Z-axis based off the tangent) then make sure to make the "Pivot" of the rotation on "Y" to be the Z-axis. ("Auto" aligns the pivot based on minimum rotation so you get disconnected rotations) .

[@ShiroiAkumaSama]

Thank you so much for explaining in a very followable and entertaining way. You really are able to make me at least "grasp" the process. Sorry for my bad English.

[@Erindale]

Perfect English! Thank you

[@nyquilthegreat]

I feel like if Erindale and Johnny Matthews teamed up they could make a functional time machine with geometry nodes

[@SpicyMelonYT]

There has never been a more accurate statement made in history!

[@stevensteverly]

lmao it's such a strange feeling when you spend 20 min trying to get your curve profiles in the right order, and then at the end of the video Math Gandalf gives you a magical combination of nodes that switches the order by x location!!

[@josephbrandenburg4373]

I am amazed to see someone else solving this problem, and with a very different (and perhaps a much more direct) solution. Mine uses curves, too - but it takes a single curve and extrudes it using the "Curve To Mesh" node. The extruded curve has the number of divisions of the desired U resolution, and the loft-curves have the number of divisions of the V resolution (resulting in a grid with the correct number of divisions in either direction). Then, I can just use the factors of the curves and a "Sample Curve" node to place the vertices... and as a consequence I can keep the factors of the curves as UV's. I added catmull-rom interpolation to it after seeing your video (I had no need for it for what I'm doing). Now it does everything yours does, and it gives me UVs (and any other data I want from the curves). But I think mine is a bit more complicated. Oh! Mine works on cyclic-curves 😊

[@Erindale]

Nice! I always love how many ways there are to solve problems when working procedurally

[@z-anatomy]

The loft and sweep functions are kinda missing in Blender; most 3D program have and them while Blender seems to re-create them only in a very complicated way. Another missing basic function is the possibility to order the elements within the collections and my main headache is that the edition of the first node of a curve affects the children for no reason.

[@man_art_man]

Insane amount of knowlege and so cool and accurate way of explanation! Love your tutorial. This special one looks like you explaining how NURBS been created in such software like Solidwork, Catia e.t.c. )))) Well done! Thanks a lot for skill share!

[@Erindale]

Thank so much!

[@Gunmetalgrey100]

At 49 minutes you say that it'll be different in Blender 4. I'm on 4.1 now. What should I change?

[@Erindale]

Your spline collection can be sorted directly without needing to go through the instance index stuff. Just plug the collection without resetting children into a Sort Elements node on the instance domain. Use position.x as the sort weight and then you want to reset the positions after which you can do with a translate instance by (-position) and then use this as the instances on your instance on points node. Make sure nothing is plugged into the instance index

[@mdriaz2002]

Just got back into blender… it’s really nice to see new methods and concepts being taught. I really liked the ordering curve thing, that thing looks useful af. As always you did an amazing job!!! Every time I see an upload by u I turn into a lil kid hahahahaah.

[@Erindale]

It's all based on your original loft setup you did for me way back 😁 glad to see you back in Blender

[@rbettsx]

Very neatly done!😀 Clear and concise! One quibble, at 40:01 .. the 2-stage alignment to a completely defined orientation. I could be wrong.. but .. I don't think gimbal lock has any bearing on the sequence of rotations.. they are *step-wise* and *local* . The basis for the second rotation is still orthogonal, after the first, there is no danger of the rotation axes coinciding. What *might* be a problem, though, is leaving both alignments 'Auto'. In your case, for example, if you first align Z to Tangent, ('Auto'), and then spin Y to (1,0,0) about the known good axis ('Z', not 'Auto') you should be OK.. 'Auto' won't throw the axis you have previously set. I'm open to correction, of course.

[@Erindale]

Hmm I'll have to double check this. You're definitely right about leaving both on auto, I should have locked the pivot of the second. I had thought with a chain of these, it's working with Eulers directly and I've definitely seen a lot of times when it's failed to correctly orient when doing Z first especially if X is after. I should read up what is actually going on there

[@rbettsx]

@@Erindale Sure. My only justification (therefore hesitancy) is testing through the front-end.. A peek at the code would nail it. 'Rotate Euler' *is* vulnerable in the way you describe.

[@shmuelisrl]

One more tip @54:00 you evaluated the index on the spline domain; I don't think this is necessary, it should already be on the spline domain since it's plugged into the reverse curve node, which evaluates on the spline domain.

[@Erindale]

I was under the same impression but for me it didn't work without it. Perhaps I had something else wrong. I should get you to vet my lesson plans 😂

[@shmuelisrl]

@@Erindale 😆. hmm, I'll have to test it. Sometimes things don't work how I thought they did, these days.

[@shmuelisrl]

@@Erindale just checked and if should work.

[@JacoblaageKragh-gc4em]

Wonderful video! But could you expand on the closed loop you make at @7:43? I'm trying to make a closed loop where the last curve is connected to the first curve, but I'm stuck :(

[@Xaqaria]

I like the controller thing because it's will let people narrow down the best 3D interface components. Blender will inherently be working with the community as it evolves to the most efficient interface options.

[@MariusBuica-m9c]

Hello, Tahnk you very very much for your tutorial. It was great. I do have however one question. If I want to close the mesh, meaning to unite the last curve with the first curve si I get a closed shape. How would I do that? Thank you very much again. you are great

[@Erindale]

Using the cylinder approach I show earlier in the video can be used with the more advanced loft to get a cyclic mesh

[@hoilumng8242]

This is what I am looking for, excellent tutorial, learned so much. Want to know how to set material along the bench which is able to bend with the curve.

[@Erindale]

You mean to follow the surface uvs? You can just store the grid UV at the end

[@Michael-rh5uo]

you are the best ! you made it simple and easy to understand thank you!

[@Erindale]

Thank you so much!

[@3d-eden978]

Truly amazing works, I learned several very usefeull things here (Cross product compare tengency 🙏). Thanks for this amazing tutorial. 😃

[@Erindale]

Happy you enjoyed!

[@BradleyMullennix-d2s]

This is absolutely wonderful.

[@__leoayres__]

Thanks for the great tutorial

[@KrazyKaiser]

I learned a lot about indices in this video.

[@johnsmith56920]

Top notch really. So many terribly useful things... Congrats and thanks.

[@shawnbecker1026]

@Erindale how would you subdivide the mesh using cm scale? So you could specify a subdivision of 10cm x 20cm?

[@Erindale]

If you’re resampling your curves to 0.1 and 0.2m then that’s the approximate subdivision you’ll end up with to the nearest whole number of divisions

[@aarcharanya]

As usual, very informative. Thank you for demystifying geometry nodes.

[@oliverfox-xi3nv]

What is the better way to do the sorting by X position in Blender 4?

[@Erindale]

I can’t remember if there was a node added or if it got ditched but it was the points to curves node and you could set the weighting for the order you wanted

[@ChrisMills-AmbientSpace]

Fantastic and nice inclusion of some vector math. Yay Dot Product! Can you please share what you are using for your keystroke display on your videos? They are nice and clear. Cheers!

[@ChrisMills-AmbientSpace]

Thanks for the answers on your Discord. Cheers.

[@thefaketomato]

Very useful, as always. Great tutorial.

[@glennet9613]

Hi. I'm interested in learning geometry nodes and you are a great teacher, but given how fast Blender geometry nodes are evolving are your courses up to date for Blender 4.0?

[@Erindale]

I’m planning a specific 4.0 course but things aren’t very different from the previous courses. It’s just that we can do more rather than existing things changing so much

[@maxthalmeier28]

Amazing stuff! Thank you so much for sharing :) One question though: I've tried a similar workflow but where the splines are closed/cyclic curves and I'm having trouble creating the remaining loft between the last curve and the first again. Any idea how that would work?

[@Erindale]

Either you can create the ribs with an extra point that exists on the position of the first so it’s technically not cyclic but visually is, complete the loft, and then merge by distance. Or you can use the cylinder method where you transfer the positions to a mesh that is already cyclic

[@JohnWesleyDavison]

Is this included in the ETK?

[@Erindale]

The loft curves node in ETK is like this but some more parameters

[@jessestapleton7277]

is it possible to do this with curves that have different resolutions, say, going from an octagon to a hexagon

[@Erindale]

No reason why not but you won't just have 8-6 on the loft. You'd want enough points to be able to handle that shape change.

[@antonioo5871]

Well explained as always:). do you know LooseEdges yt channel? I recently watched his Build nodes assets video which tackles parametric design. It seems like an interesting topic to work on in geometry nodes.

[@Erindale]

I do not, I'll check them out. Thanks for the heads up!

[@benjaminsmith4221]

Is it possible to loft curves with identical points and preserve the original spline count.

[@Erindale]

Like the simple loft I did at the start of the tutorial or something else?

[@TynkaTopi]

Thank you ! How to use this when using only one 1spline curve in collection and it has mirror modifier ?

[@Erindale]

What is it you want the mirrored curve to be doing? How do you want to the final mesh to look?

[@TynkaTopi]

@@Erindale For example half of the skateboard, longitudinal direction. With one spline you can also make both ends upwards and with the top view you can make a shape. puu.sh/KgCnO.jpg

[@Erindale]

@TynkaTopi to loft a skateboard shape it would be easier to imagine it like taking a skate deck and cutting through it with a saw lots of time. The slices that you’d see are the profiles and the line down the centre of the board would be the path. Then you can loft those profiles along the path to get the shape again

[@TynkaTopi]

@@Erindale Yes, I'll try that way. With that method, you can do it accurately even if the board is concave in the middle.

[@hadriscus]

I've been hoping for rotation order to become a setting in the "align rotation to vector" node, do you know if that's planned ?

[@Erindale]

There were some mockups I think on the git pages but I'm not sure it went anywhere. It seems like it would be useful for sure

[@hadriscus]

@@Erindale alright. Perhaps obsolete now that there's a quaternion type

[@samcollins7633]

hey friend. i recently listened to your podcast with Andrew Price and I was intrigued by your discussion on geo nodes and learning shader nodes with a flat plane and just messing with nodes to visually see the output and learn that way. I think this is really interesting because it is similar to how Cartesian Caramel says he learned. Id be interested in seeing a demo or like your process or suggestions on that.

[@Erindale]

Take a look at my early shader tutorials doing things like herringbone or making shapes. I basically just did that kind of thing for a year or two. Look on Twitter at nodevember hashtags as well. 2019 and 20 were the best years as we were all playing with vector displacement. I have videos showing mine from then as well on this channel

[@JohnnyThund3r]

Hmmm... this is super helpful... Between this and Blender Sketcher, I'm trying to think why I would still need to learn Freecad when I can just loft things in Blender and control the topology better that way?

[@Erindale]

If you need super accurate technical drawings then CAD software but pretty much everything else, Blender does fine 🤌

[@randelmatt]

Blender 3.6! Man, where have I been??

[@eliaspierre6303]

Is there anyway to make the loft cyclic?

[@Erindale]

What I showed earlier with the cylinder. That can be applied to the complex loft as well

[@eliaspierre6303]

@@Erindale okay awesome! Thank you!

[@eliaspierre6303]

I wasn’t t able to get that method to work but I found another way that atleast works for the smoothed version of it

[@victorradical9995]

@@eliaspierre6303 can you explain a little? please

[@affyrainbows5415]

Thank you Thank you Thank you Thank you!!!!

[@gooorylin]

Sir - you are very clever person! the way you have done it,it seems to be quite complicated.I will now start using: geometry nodes.Blender is getting similar to houdini.I will now be learning geometry nodes,because of its endless possibilities.Have you done on your own that loft or have you learned,how to create it?

[@Erindale]

Once you’re more comfortable with the workflow, coming up with solutions like this is fairly straightforward. It’s just learning to think that way that takes time

[@chrisgreenwell3404]

Fantastic , thank you :)

[@Erindale]

Glad it's useful!

[@shmuelisrl]

Erin 🫣 why did you do that whole convoluted thing for the liner interpolation instead of using a subdivide curve node? (You could have also just used the original curves and two sample index's and used the uv's to interpolate with some math, but I'm not gonna hold you on that one. However, this whole ctm, mtc, merge by distance mishegas seems kinda overboard 🤔)

[@Erindale]

Oh mainly (entirely) because I forgot that node exists 😁

[@shmuelisrl]

@@Erindale 🤣

[@michaelvaughan2986]

What if the two curves are circles?

[@Erindale]

You will be missing the final connecting faces so you either want to use a mesh like the cylinder which already has those faces, or you want to replace your curves with something like a spiral that goes back over itself and then merge doubles after the loft.

[@osmodivs]

That's just too much... How do you figure out that setup!?

[@linlin-ik7zh]

There is sth wrong with flipindex？modulo3 maybe???

[@Erindale]

In the tutorial or in ETK?

[@linlin-ik7zh]

@@Erindalein the tutorial.15:44my order-modulo3-multiply12-add1-divide3-floor-output

[@linlin-ik7zh]

I don’t know why

[@eobet]

Why isn't there just a "bridge edge loops" node? 😭

[@Erindale]

The design for this kind of thing is surprisingly complex in procedural modelling. Which edge loop pairs, what resolutions, what interpolations etc. We’ll get one eventually 😁

[@OrangeJambo]

phhhhheeewwww

[@Bleenderhead]

A bench? It looks more like a discarded banana peel. Not the most motivating example.

[@Erindale]

Onus is on you to make something you want with the information 👍

[@Bleenderhead]

@@Erindale I have since chosen to think of it as a shape you can make by smoothly modulating the shape of your sphincter. Now I am far more motivated.

[@mrofnoctonod]

@@Erindale Looks like someone hasn't taken their meds today. Thanks for sharing!

[@gottagowork]

We've had several projects coming from architects where bench furniture in these kinds of shapes have been indicated. This is a perfect tool for that. I'll only note that it falls short compared to Solidworks lofting wrt end tangent controls. That's due to our Catmull Rom implementation not allowing bezier control over end tangents. Discarded banana peel? Wtf? 😂

[@Erindale]

You could definitely expand the tool to give you bezier tangent controls of the rib curves. You wouldn't get any 3D viewport gizmos to control it but you can make whatever you want with enough nodes 😁