Draw Guides Modifier
Draw a stroke on the scalp and that stroke is a guide — its shape, its length, its direction, all from the one gesture. Then fill in between your strokes with interpolation.
When to use: blocking out a groom from nothing, hero strands you want to place exactly, fringes and partings, and any shape that is quicker to draw than to dial in. It is the fastest way from a bare mesh to a groom that reads.
The idea
Placing guides and then combing them is two passes over the same surface, and the second pass is most of the work. Drawing skips it: you draw the hair's silhouette and that is what you get.
One stroke, one guide. Nothing is multiplied behind your back. Filling in around your strokes is a separate, explicit choice.
Drawing
Add a Draw Guides modifier and press Draw Guides in its panel.
| Input | Action |
|---|---|
| Drag | Draw a guide |
| Hover + Del / Backspace | Delete that one stroke — it turns red under the cursor first |
| Ctrl + Z | Undo the last stroke |
| X | Clear every stroke |
| Wheel / [ ] | Scatter radius (only used when Interpolate is on) |
| Esc / RMB | Finish |
Deleting one stroke
Move the cursor over a stroke and it lights up red — that is the one that will go. Press Del (or Backspace) and it does, and nothing else moves.
The strokes are independent, so this is safe rather than merely convenient: every stroke is scattered from its own seed in its own frame, so a drawn guide depends only on the stroke that made it. Delete the first, middle or last of three and the survivors come back bit-identical — measured, not asserted — even though every one of them shifts position in the list.
The one thing a delete does move is the interpolated fill. Those guides are blended from the ones you drew, so removing a source necessarily re-blends them. The guides you drew yourself are untouched either way.
If you want everything gone, X in the tool or Clear Strokes in the panel still does that in one step.
Where the stroke goes
The first point of your drag must land on the mesh — that is the root, and hair grows from somewhere. Everything after it is drawn in the plane facing you through that root.
That is what lets you draw a silhouette: swing the stroke up and away from the surface and the hair stands up, exactly as you drew it. If every point were projected onto the mesh the guide would lie flat on the scalp and could never leave it.
Practical consequence: orbit to the angle you want to judge the silhouette from before you draw. You are drawing in the plane of the screen, so the view is part of the gesture.
Guide
| Setting | What it does |
|---|---|
| Length | Multiplier on the length you actually drew. 1.0 is the gesture as made. |
| Points | Control points per guide. Raising it re-reads the stroke you drew, so the shape follows your path more closely — it is not subdividing an approximation. |
Both are live. Draw first, adjust after — the strokes are the data and the guides are rebuilt from them every time.
Interpolate
| Setting | What it does |
|---|---|
| Count | Total guides after interpolating between the ones you drew. 0 keeps just your strokes. |
| Variation | Length and shape randomness on the interpolated guides only. |
| Seed | Reshuffles the interpolated guides. |
The extras are blended from the shapes you drew and scattered across the surface — three strokes down an animal's back become a groom. Guides you drew are never altered by it; the interpolated ones are added alongside.
Surface
| Setting | What it does |
|---|---|
| Avoid Surface | Push guide points that land inside the mesh back out. On by default. |
| Offset | How far off the scalp to hold the corrected points. |
Because the stroke is drawn in the plane facing you, on a curved head part of it lands inside the mesh — and there is no angle from which you can see that happening while you draw. Avoid Surface fixes it afterwards, keeping every segment length so the guide wraps the surface instead of being shortened.
On a strongly curved mesh, "exactly the length I drew" and "strictly outside the surface" cannot both be guaranteed. Length wins, and Offset is the lever for the small remainder — raise it if a guide still grazes the scalp.
Also Set Direction
On by default. Each stroke's direction is also written into the painted flow field, so one gesture both creates the guide and combs the hair around it. Needs a Guide Flow modifier with Surface Field enabled to have any effect; harmless otherwise.
It is fully procedural
The strokes are what is saved. The guides are derived from them on every evaluation, which means:
- Length and Points reshape guides that already exist
- Disabling the modifier removes its guides; enabling brings them back unchanged
- Clear Strokes removes exactly the guides those strokes made
- Adding a stroke never disturbs the guides an earlier stroke produced
- Deleting one stroke removes exactly its guide and leaves every other one identical
- The result is identical every time it re-evaluates
Nothing is baked, so Draw Guides can sit anywhere in the stack and be reordered against Flow, Clump and the rest.
One groom at a time
The tool edits the hair system selected in the Hair System dropdown — the same one whose modifier stack you are looking at. On a character with several grooms (a scalp plus brows, or two systems on one head), switch system in the dropdown and the Draw Guides button, the strokes and Clear Strokes all follow it.
If the button reports "No Draw Guides modifier on the active hair system", the system you are on does not have one. Add it there, or switch to the system that does — the tool will not reach into a groom you are not looking at.
Workflow: blocking a groom
- Select the scalp mesh, add a Draw Guides modifier.
- Orbit to a silhouette view. Draw 4–8 strokes describing the main shapes — the fringe, the part, the sweep at the sides.
- Set Interpolate → Count to a few hundred. The gaps fill in.
- Adjust Length and Points until the shapes read.
- Add Guide Flow and paint or draw flow on top if you want finer direction control between the drawn shapes.
You do not need to generate guides first — a Draw Guides modifier can be added to a bare mesh and will create the hair system for you.