Curl Modifier
Pro edition. Curl is included with Pro alongside Braid, Cornrow and Loc. The Community edition includes the Coil modifier, which produces per-strand helixes, waves and corkscrews.
Curl curls the guides — so the curl is structure the strands interpolate, not a wobble added to each hair afterwards. That is what makes coils coalesce into ringlets instead of every hair wandering off on its own.
When to use: waves, barrel curls, ringlets, spiral perms, roller sets, crimp. Anything where the shape of the hair is the curl.
Curl vs Coil
They sound alike and do different jobs.
- Coil displaces each rendered strand around its own axis, after interpolation. It is a per-hair perturbation — good for fine variation and for breaking up a groom that reads too clean.
- Curl edits the guide's curvature before interpolation. Every hair in a clump follows the same curl, so the curl reads as one coherent lock rather than a thousand independent wobbles.
The two stack. A common setup is Curl for the shape and Coil for per-hair variation on top.
Two things that follow from how it works
The length never changes. Curl edits curvature rather than pushing points around, and arc length is what the maths integrates along. Curling draws the tip in toward the root — what a roller set physically does — instead of growing the hair.
Plan for that. Tight curls consume length: at ringlet settings the tip ends up only about half the strand's length below the root. For a curly look that reads 25 cm long, generate guides about 50 cm long. Build them at the finished length and you get a bob.
Two Curl modifiers add together, in any order. Curvature adds, so a soft base wave under a tight tip curl is a normal way to work. A negative Curl on a second modifier relaxes the first — that is how you straighten a region without deleting the modifier that curled it. (The one exception to order-independence is Coils Around; see below.)
It ships curling
Add a Curl modifier and you get ringlets straight away — Define By Size + Turns, Coil Size 0.016, Turns 9, Coils Around Fall line, Resample 150. Set Curl (or Amount) to 0 for a true pass-through: the guides come out bit-for-bit unchanged.
Only three controls do anything on their own
Curl, Twist and Wave. Everything else shapes what those produce — Ellipticity needs a coil to flatten, Switchbacks need torsion to reverse, the profiles need something to profile. Set one of the three first, then shape it.
Curl
Curl
- The tightness. What the number means depends on Define By
- Negative curls the other way, and cancels an earlier Curl exactly
Define By — what the Curl number is measured in
- Curvature — a fixed radius in scene units. A longer guide simply gets more coil
- Turns — wraps over the guide's own length, whatever that length is. This is the roller set
- Size + Turns — Curl becomes the coil radius as a fraction of the strand, and Twist becomes the turn count. Reach for this when you want a specific ringlet
Under Size + Turns the panel relabels itself: Curl becomes Coil Size and the Twist section becomes Turns.
The ceiling. A ringlet has two properties — how big, how many turns — and they trade against each other. One loop costs its own circumference in hair, so:
turns ≤ 1 ÷ (2π × radius)| Coil Size | Most turns possible |
|---|---|
| 0.045 | 3.5 |
| 0.030 | 5.3 |
| 0.020 | 8.0 |
| 0.012 | 13.3 |
Ask for more and the coil flattens into a spiral with no descent, so the panel shows the limit live and turns red when you cross it. Tight ringlets naturally sit just under the ceiling — that is what makes them tight.
Coils Around — what a ringlet wraps around. This decides whether curls hang or fly outward.
- Nothing — the coil's axis lands wherever the maths puts it, and a tight coil swings the hair off its fall line. Correct for flat spirals and roller sets that are meant to swing out
- Fall line — the coil wraps around the way this hair hangs, so it corkscrews downward. Use this for ringlets
- Straight down — pinned to world gravity regardless of how the guides were combed
The one trade-off in this modifier. Pinning the axis makes Curl modifiers order-dependent. Everywhere else curvature simply adds; aiming a coil at a fixed direction depends on where the strand has already got to. Stacking still works, lengths stay exact — it just is not the order-doesn't-matter guarantee the rest of the modifier gives. Pin the axis on the modifier that makes the ringlet, leave it off on ones that only shape.
Curl Profile
- Tightness along the guide — root on the left, tip on the right
- Flat is a constant radius root to tip: a perfect spiral, which no head of hair has
- Draw it rising for straight roots and tight ends
Ellipticity
- The coil's major:minor ratio.
1is round;4is four times wider than deep — a ribbon curl, which is what real hair usually is - Needs a coil to act on
Wave
Wave is a planar alternating bend — finger waves and crimp, not coils. It adds to Curl rather than fighting it. Cycles sets how many fit along the guide, and low is what looks like hair: 2 to 3 for a beach wave. Higher values give a ripple at frizz scale.
Wave still hangs where Curl does not. A constant curvature must bend the path the same way throughout, so Curl carries the hair off its fall line unless Coils Around is set. A wave alternates, so it averages out and the strand keeps falling.
Wave Profile shapes the amplitude along the guide. Draw it rising and the waves grow toward the ends, which is what brushed-out curls do.
Twist
Twist is torsion — it turns a flat curl into a corkscrew. Its sign is handedness: what barbers call S-twist versus Z-twist.
Switchbacks are handedness reversals along the strand, characteristic of tightly coiled hair where a single strand does not keep one handedness end to end. They modulate Twist, so they do nothing on their own.
Switchbacks cost turns. A reversal unwinds what came before it: at Coil Size 0.016 / Turns 9 the net winding is 8.9 turns with none and about 4.5 with any. Turns still says what is wound; it stops saying where the tip ends up.
Straight ends after a curl
When a pinned coil stops, the hair does not straighten downward — it leaves on a tangent at the coil's angle and flies outward. Fading the Curl Profile does not help, because a tangent that has stopped turning just freezes where it is.
Fade the Curl Profile and leave the Twist Profile flat. That collapses the coil angle and walks the tip back onto the fall line. Measured off-vertical at half / three-quarter / full length: 58°/58°/58° with both faded, 58°/40°/7° with only the curl faded. That is how you get ringlets at the roots with ends that still hang.
Region
One curve over the whole modifier. It scales Curl, Twist and Wave together, on top of each one's own profile.
- Flat at the top masks nothing — that is the default
- Drag the left end down for straight roots
- Drag the right end down to release the tips
Region and the three Profiles only ever scale toward zero. Nothing in either makes a curl tighter than the number you typed — that is what the Curl Profile's shape is for.
Output
Amount scales everything the modifier adds. 0 is a genuine off — the guides pass through untouched, bit for bit.
Variation is per-guide spread in tightness, phase and handedness. 0 is uniform: waves line up across guides and Twist keeps the handedness you gave it. It is drawn from each guide's stable ID, so it never reshuffles when the guide count changes.
Resample: use about 12 × Turns
A curl needs enough points to carry it. Below roughly 10 segments per turn the coil starts flattening — quietly, because the length stays exact either way and only the shape degrades.
| Look | Resample |
|---|---|
| Beach waves, 2–3 cycles | 150 |
| Barrel curls, 4–6 turns | 200 |
| Tight ringlets, 9–12 turns | 250–350 |
Recipes
Long waves, straight on top
Two modifiers — one for body, one for the ends.
Body: Wave 20, Cycles 3, Twist 4, Variation 0.4, Wave Profile rising from 0 at the root to 1 at the tip.
Ends: Curl 13, Twist 8, Coils Around Fall line, Variation 0.4, Curl and Twist Profiles flat 0 until 55%, rising to 1 by 78%.
Tight spiral ringlets
One modifier. Define By Size + Turns, Coils Around Fall line.
- Coil Size
0.016, Turns9 - Ellipticity
1.3, Variation0.35 - Region flat 0 to 6%, up to 1 by 16%
- Resample
150
Tighter: Size 0.012 / Turns 12, Resample 200. Chunkier: Size 0.020 / Turns 7, Resample 120. Remember the guides need to be about twice the finished length.
Roller set
Define By Turns, Curl 2.5, Twist 0, Coils Around Nothing. A planar coil that swings out is exactly what a roller set is.
Scene scale
Curl in Turns, and everything under Size + Turns, are scale-free — they are ratios, so a recipe transfers between grooms. Double the guide length and you get a proportionally bigger coil with the same number of turns.
Twist in Curvature mode is not. Torsion is a 1/length quantity, so Twist 8 means different shapes on guides of different lengths. Divide it by your guide length: on 0.5-unit guides use 16. This does not apply under Size + Turns, where Twist is a turn count.