Houspider

A procedural spider model generator for SideFX Houdini. It exposes the most useful shape and topology controls as editable Houdini parameters.

Adjust the parameters to explore different spider shapes. Enter obj/spider/skeleton/animate_scene and enable Animate View to pose the limbs.

This project wish to explore and experiment with fully procedural, code-driven organic modeling.

How it works

The generator uses Houdini Python (Houdini Object Model) to create and connect the modeling network. It heavily relies on Houdini's attributing system to identify points and faces. It still builds in node networks to mkae inspection and debugging easy.

The project uses houkit for reusable Houdini node, parameter, and attribute helpers.

Quick start

You need Houdini with hython available on your PATH.

1. Install dependency houkit:

hython -m pip install git+https://github.com/red-bean-pasta/houkit.git

2. Clone this project:

git clone https://github.com/red-bean-pasta/houspider.git
cd houspider

3. Build the example Houdini file:

hython scripts/build_test_hip.py

The model is then output to test/test.hip.

Examples and topology views

Current limitations and TODOs

• Add a complete subdivision workflow; it's currently low-poly.
• Add eyeballs.

Parameter reference

These top-level parameters on /obj/spider let you shape the body, limbs, and poses without diving into node networks.

Prosoma & Carapace (Head & Main Body)

Parameter	Description
Front / Back Length	Length of the front and back of the main body.
Top Height	How tall the upper body is.
Top Width / Length	Width and length of the top surface.
Chelicerae Height	How high the fangs sit on the body.

Chelicerae (Fangs)

Parameter	Description
Middle Section Size & Offset	Thickness and outward curve of the middle of the fangs.
End Section Size & Offset	Tip sharpness and how far down the fangs reach.
End Section Rotation	Inward and downward angle of the fangs.

Abdomen

Parameter	Description
Width / Height / Length	Width, height, and length of the rear body.
Constant Width Range	How far the rear body stays wide before tapering.

Legs

Parameter	Description
Coxa Length	How far the legs extend before the first joint.
Segment Lengths	Length of each leg segment.
Other Leg Lengths & Widths	Length and width of the middle and back legs relative to the front legs.
Segment Profiles	Thickness profile along each leg segment.
Joint Limits	Bending limits for each joint.
Rest Flex Ratios	How bent the legs are in their rest pose.

Pedipalps (Front Feelers)

Parameter	Description
Coxa & Segment Lengths	Length of the front feelers.
Endite Length & Surface Size	Size of the mouth plates beside the fangs.
Rest Flex Ratios	How curled the front feelers are in their rest pose.

Fine-tuning details, like seam widths, junction tolerances, and internal clearance angles, are left off this list. Explore the full parameter set, including the Advanced controls, directly on /obj/spider in test/test.hip.

Acknowledgements

This project is manually directed, reviewed, structured, and tested at the method level. AI assists with implementation within that process.