Aaron Smith’s hPaint update takes something similar to Blender’s Grease Pencil in Houdini to new levels, supporting Houdini 20.5 with several fresh capabilities for streamlined, detail-rich annotations and drawings. Houdini users in VFX, real-time graphics, game development, and digital production can now leverage the 2D Grease Pencil as a more powerful tool for creative mark-ups, thanks to improvements like brush size and color management, layer controls, and real-time annotation tweaks within the Houdini viewport.
Overview: What hPaint Brings to Houdini
With hPaint, the open-source Grease Pencil workflow has been simulated, allowing Houdini users to switch between technical drawing and real-time visualization within the same environment. Artists can apply these features for shot planning, rough storyboards, and live-action frame annotations, addressing the practical demand for efficient drawing capabilities directly in Houdini’s node-based setup.
- Brush Controls: The update includes brush size adjustments and refined color management to give users more control over how Grease Pencil annotations appear within scenes.
- Layer Management: The new layer functions mean artists can structure annotations without clutter, a bonus when working with complex scene compositions.
- Viewport Improvements: hPaint now offers more responsive updates in the Houdini viewport, creating a more intuitive experience for artists who need direct feedback while drawing.

Practical Use Cases
For Houdini users, these updates present possibilities for streamlined workflows. Grease Pencil in Blender has historically been useful for 2D mark-ups and reference sketches, and it’s cousin might do the same for Houdini users not working in Hand-drawn styles. Nothing beats a handwritten mark on an asset. “Get your shit together, pickles!” , or a friendlier “Nicely done.” Whatever your supervisor chooses for communication.
Stability, Price, and Availability
Although promising, any newly integrated tool, especially within complex software like Houdini, should be tested for stability in production pipelines before use. hPaint, being open-source, is freely available on GitHub, making it accessible to any Houdini user looking to expand their annotation toolkit without extra cost.
Fact-Check Note
Given the variety of workflows in production environments, professionals should evaluate hPaint’s stability and integration with their current Houdini setup, especially for projects demanding robust, interruption-free performance.