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For those who don’t know the tool: Roman Gibadullin, publishing as iltaen, is a 3D low-poly artist; Blender is the host DCC for modelling, rigging, animation and rendering. Spider Walker is his small Blender add-on for the animation stage, taking an existing armature and driving its leg controllers procedurally against scene meshes before baking the resulting motion into a regular Blender Action for downstream editing and rendering.
Spider Walker tackles a very particular animation problem: getting a spider-like rig to move its collection of legs without asking an animator to place every foot manually. If you want to spend as little time as possible with spiders because, like us, you’re a bit of an arachnophobe, this is the tool for you: animate the body and let Blender deal with the legs.
The add-on by Roman “iltaen” Gibadullin procedurally calculates where the feet should plant as the body moves, projects those targets onto scene geometry and generates stepping motion between planted positions. The resulting procedural movement can remain live while an animator works, then be baked into a keyframed Blender Action when it is ready for “ordinary” animation work.
Move the body, outsource the legs
Spider Walker starts from an existing Blender armature rather than generating a creature rig. The animator identifies the armature, chooses a Center Bone representing the body or root motion, and assigns the controller bones used to position the legs. Those controllers would typically be IK targets or other independently poseable bones responsible for foot placement.
The important division of labour is that Spider Walker does not attempt to animate the entire character. The body motion remains an upstream input. The add-on observes that motion and derives leg placement from it, making this closer to a procedural locomotion layer than an automatic character-animation package.
The current source code is version 1.0.6 and targets Blender 5.2. The repository documentation specifies Blender 5.2 or newer. Blender 5.2 is an LTS branch supported by the Blender project until July 2028, which makes the host requirement more interesting for studios than a dependency on an experimental daily build would be.
A gait from rig state, not magic
The stepping logic begins with the Center Bone. Spider Walker reads its world-space position and estimates body velocity. Each configured leg has a rest relationship to the body, and the system uses that relationship to calculate where the foot would ideally be as the character moves.
Rather than simply dragging this rest position after the body, the add-on can predict movement ahead of the current position. The Prediction Distance control determines how far forward a leg target can be shifted according to travel direction. Setting Prediction Distance to zero disables that predictive behaviour, leaving the feet to follow the body’s current position instead.
Spider Walker then compares the currently planted foot position with the newly calculated target. Once the distance becomes large enough to satisfy the stepping condition, the leg transitions towards a new planting point. The leg list also defines gait order, giving the animator direct control over the sequence in which the configured controllers participate.
This is procedural animation in the fairly literal sense. The runtime system calculates targets from transforms, velocity, stored leg state and collision queries. It is not a generative-animation model deciding that a spider looks emotionally prepared for leg number seven.
The floor joins the rig
Ground contact comes from a Collision Collection containing the mesh surfaces Spider Walker should consider walkable. The add-on evaluates meshes in that collection and raycasts towards them from the calculated foot targets, selecting a hit position and surface normal for the new plant.
Probe Distance controls the distance over which the tool looks for a usable surface. That matters on uneven terrain, where a probe that is too short may never reach the geometry beneath the predicted foot. Surface Offset then moves the resulting target along the hit normal, which is useful when an IK controller’s pivot does not correspond exactly to the visible sole, claw or tip of the creature’s foot.
The repository contains a worthwhile production warning here. The actual foot raycast examines visible mesh objects in the selected collision collection. Character geometry should therefore not casually share the same collision collection as the terrain. Otherwise the creature can provide its own walking surface, which is technically resourceful but rarely the requested performance.
One hierarchy rule bites back
The most important rig requirement concerns parenting. A configured leg controller must not be a direct or indirect child of the Center Bone. Spider Walker calculates and applies leg placement relative to that Center Bone’s movement. If a leg controller already inherits the Center Bone transform through the armature hierarchy, it effectively receives that movement through the rig and again through Spider Walker’s placement logic. The developer describes the resulting behaviour as incorrect or unstable leg positioning.
The useful knobs
The main artist controls stay focused on locomotion rather than exposing every internal calculation. Step Distance defines how far a planted foot may drift from its current target before another step is triggered. Lower values therefore produce more frequent repositioning, while larger values allow the foot to remain planted for longer.
Step Speed controls the base movement speed during the swing, while Step Height determines the vertical arc of the foot. Minimum and maximum step times constrain how short or long the swing may become, preventing tiny movements from collapsing into an instant snap or long moves from wandering towards their target indefinitely.
Prediction Distance affects where the next target lies relative to movement. Combined with Step Distance, Step Speed and Step Height, it gives an animator a small but useful behavioural vocabulary without requiring hand-authored foot contacts for every translation of the body.
The individual leg entries can also be reordered or disabled. That is particularly useful when evaluating gait structure because the underlying rig remains intact while individual controllers can temporarily drop out of the procedural sequence.
Blender plumbing stays local
Spider Walker is distributed as Python source and uses Blender’s own Python APIs, including bpy and mathutils. Its collision calculations operate on evaluated Blender mesh objects and use Blender ray-cast queries. The repository does not document an external solver service or cloud-processing dependency.
AI helped write it, not walk it
Gibadullin explicitly discloses that parts of Spider Walker’s code were created and refactored with AI assistance. That provenance should not be confused with the runtime animation method.
The documented walking system is based on conventional procedural logic: transforms, velocity estimation, rest offsets, step state, target prediction and mesh raycasting. In other words, AI assisted with some of the software development, but the spider is not sending its feet to a foundation model for career advice and crunch a few Tokens.
Small scope, useful boundary
Within its documented scope, the appeal is easy to understand. A body animation becomes an upstream driver, ground meshes provide contact information, Spider Walker generates the repetitive foot-placement layer, and baking turns the result back into ordinary keyframed animation. The artist still owns timing, posing and final polish, but fewer legs need individual babysitting during the procedural stage. And far fewer hebbie-jeebies when staring at a bloody eight-legged spider all day!
| Product | Spider Walker |
| Developer | Roman Gibadullin / iltaen |
| Version | 1.0.6 |
| Host compatibility | Blender 5.2 or newer |
| Production role | Procedural leg placement and animation baking for multi-legged rigs |
| Rig requirements | Armature with Center Bone and independently poseable leg controller bones that are not descendants of the Center Bone |
| Collision input | Blender collection containing visible mesh surfaces used for foot raycasts |
| Output | Baked keyframed Blender Action |
| Licence | MIT |
| Availability | Public GitHub repository |
| Documentation | Repository README |
| Download | GitHub repository |
