Create Pulsing Shapes From Scratch With The Pen Tool

How to Create Pulsing Light Shapes From Scratch With the Pen Tool

This tutorial builds a set of custom, heartbeat-like light shapes entirely from scratch using the Pen tool and a stroked brush path, then scatters them across a product shot to create a glowing, organic effect that would be nearly impossible to draw freehand with a mouse. Along the way it also covers a quick trick for stretching out a distracting light streak in the original background before any of the custom shape work begins.

Stretching the Background to Remove a Distracting Light Streak

Before adding any new shapes, a light streak curving back into frame in the original photo needed to be stretched out of the way so it wouldn’t compete with the new effect.

1. Duplicate the Background and Select the Streak

   Press Cmd/Ctrl+J to duplicate the background layer, then use the Marquee tool to select the area containing the distracting light streak.

2. Feather the Selection With Quick Mask and Gaussian Blur

   Press Q to enter Quick Mask mode, apply a Gaussian Blur to soften the mask’s edge, then press Q again to return to a normal, feathered selection.

3. Stretch the Selection With Free Transform

   Press Cmd/Ctrl+T, drag the side handle to stretch the selected area to the right, and press Enter to commit. Press Cmd/Ctrl+D to deselect once the streak is stretched out of the way.

Why Quick Mask Beats a Numeric Feather Value

Feathering a selection through Select > Feather requires guessing at a radius without seeing the result until after it’s applied. Quick Mask shows the blur directly as you apply it, which makes it much easier to judge exactly how soft the selection edge needs to be before committing to a transform.

Drawing a Pulse Shape With the Pen Tool

The heartbeat-like shape at the center of this effect starts as a simple path built point by point with the Pen tool.

4. Create a Temporary Layer for Visibility

   Add a new white layer purely so the path is easier to see while drawing — this layer gets deleted once the path is finished.

5. Click and Drag to Build the Path

   Select the Pen tool and click-drag to place a series of anchor points that trace a rising and falling line, similar to a heartbeat monitor readout, adjusting the drag direction at each point to control the curve.

6. Adjust Anchor Points as Needed

   Hold Cmd/Ctrl and click an anchor point or its handle to move it, refining the shape of the path until the peaks and curves look natural.

Why the Pen Tool Is Easier Than Its Reputation Suggests

The Pen tool has a reputation for being difficult, but building a path is really just a sequence of click-drag placements followed by small adjustments made by Cmd/Ctrl-clicking points and handles. Once the temporary visibility layer can be deleted, what’s left is a clean, fully editable path that can be reused as many times as needed.

Turning the Path Into a Brush Stroke With Pressure Simulation

A path by itself is invisible in the final image — it needs to be stroked with a brush to become a visible shape.

7. Choose a Soft Round Brush

   Select the Brush tool, set the foreground color to white, and choose a soft round brush with a moderate hardness (about 47% Hardness at size 12 in the video), adjusting size to taste for the shape you’re building.

8. Stroke the Path With Simulate Pressure Enabled

   Right-click the path in the Paths panel, choose Stroke Path, select Brush as the tool, and check Simulate Pressure. This makes the stroke start thin, thicken through the middle, and taper back down, mimicking a naturally drawn light trail rather than a uniform-width line.

Why Simulate Pressure Matters for Organic Shapes

Organic light shapes and rays almost always taper at both ends rather than holding one consistent width, and that kind of variation is difficult to draw by hand with a mouse. Simulate Pressure builds that natural thin-thick-thin taper into the stroke automatically, which is what makes the resulting shape read as organic rather than mechanically drawn.

Building Multiple Variations From the Same Path

The same path can be restroked with different brush sizes to build a family of related shapes rather than a single fixed one.

9. Restroke the Same Path at Different Sizes

   Create a new layer, adjust the brush size, select the same path again, and repeat Stroke Path to produce a thicker or thinner version of the same underlying shape, keeping the ones that look useful and discarding the rest.

Adding an Outer Glow to the Stroked Shape

A flat white stroke reads as a hard line rather than glowing light, so a layer style adds the missing dimension.

10. Apply an Outer Glow Layer Style

    Double-click the stroked shape’s layer to open Layer Styles, choose Outer Glow, set a color that fits the image’s palette, and adjust the Spread and Size until the glow feels proportional to the shape.

Duplicating, Fading, and Adding Imperfection

A single perfectly clean glowing shape can look a little too digital, so a few extra passes help it feel more integrated into the photo.

11. Duplicate, Scale Down, and Lower Opacity

    Press Cmd/Ctrl+J to duplicate the glowing shape, press Cmd/Ctrl+T to scale a copy down, and lower its opacity to create a fainter secondary layer with a slightly different scale.

12. Paint in Extra Imperfection

    With the Brush tool, paint a few additional soft strokes directly onto a layer, then hold Alt/Option and drag the Outer Glow effect from an existing layer onto the new one to copy the same glow style across.

Why a Little Imperfection Sells the Effect

A perfectly uniform, mathematically clean shape is one of the fastest ways to make an effect look obviously computer-generated. Adding small hand-painted variations and copying layer effects across them, rather than duplicating one flawless shape repeatedly, keeps the result looking closer to something organic that simply happened to be captured in the photo.

Grouping and Scattering the Pulses Across the Image

With one complete pulse shape built from several layers, the last step is turning it into multiple instances placed around the image.

13. Group the Shape’s Layers

    Shift-click every layer that makes up one pulse shape and press Cmd/Ctrl+G to group them into a single unit.

14. Duplicate and Transform the Group

    Press Cmd/Ctrl+J to duplicate the entire group, then press Cmd/Ctrl+T to scale, rotate, and reposition the copy so it follows a different line or curve in the image. Repeat as many times as needed to scatter the pulses naturally across the photo.

Why This Approach Works

Building a light shape from a Pen tool path rather than drawing it freehand solves a real problem: the Pen tool produces a precise, fully editable curve that can be restroked at any size, with any brush, as many times as needed, while a freehand brush stroke is a one-shot commitment. Enabling Simulate Pressure when stroking that path is what gives the result its organic, tapering quality without requiring an actual pressure-sensitive tablet. Layering an Outer Glow style on top, then duplicating the whole group with small variations in scale, opacity, and hand-painted imperfection, is what turns one clean vector shape into something that reads as a naturally occurring light effect scattered across the photo rather than an obviously repeated graphic.

Final Thoughts

The specific heartbeat-like shape used here is just one example — the actual reusable technique is building any custom curve with the Pen tool, then stroking it with a brush using Simulate Pressure to get a natural taper. Once that base shape exists as a group, layer styles like Outer Glow and simple duplication with scale and rotation changes let you multiply it into as many variations as a scene needs. This same combination of Pen tool paths and stroked brushes works for far more than light effects, too — any custom line, swirl, or organic shape you can’t draw convincingly by hand is a good candidate for this workflow.

Quick Reference: Keys, Menus and Settings

• Soft selectionM Marquee, Q Quick Mask, Gaussian Blur, Q again
• Stretch itCmd/Ctrl + T, drag the side handle, Enter; Cmd/Ctrl + D
• Draw the pathP, click and drag each point; Cmd/Ctrl-click to move points and handles
• BrushB, white, soft round, Hardness about 47%, size 12
• StrokePaths panel, right-click > Stroke Path, Tool: Brush, Simulate Pressure on
• GlowDouble-click the layer > Outer Glow: color, Spread, Size; Alt/Option-drag to copy the effect
• ScatterCmd/Ctrl + G to group, Cmd/Ctrl + J to copy, Cmd/Ctrl + T to place

No AI, no generative credits.