Houdini 17.5 Shelf tools

Muscle Rig shelf tool

Creates the internal components of a muscle (the rig), by stroking a curve onto a skin object.

This tool creates the control components of a muscle. You would typically want to do this if you intend to build a muscle comprised of custom modeled geometry, and one or more rig systems. This will give you the ability to have multiple attachment points for arbitrarily shaped muscles. It is very similar to the Stroke Muscle tool, since it prompts you to select a skin object and lets you stroke a curve over the skin.

This tool creates a Muscle asset that is identical to one created with the Muscle and Stroke Muscle shelf tools, but will only display visibility for the rig components (the muscle geometry in this asset is ignored and only the inner core and handles are toggled on).


You can control the radius of the rig’s inner core by scrolling the mouse wheel or holding ⇧ Shift while dragging to resize your brush. This inner core will be used as the capture points for deforming muscle geometry.


Creating muscles rigs will leave the endpoints detached from your character rig. They will be drawn in worldspace and consequently should be drawn over your skin in its rest position (ie, T-pose). You can connect the head and tail anchors later using the Attach to Bones shelf tool.

The capture pose for the inner core is automatically set to match the stroked position. If rig handles are further adjusted by repositioning them in the viewport, the capture position will need to be reset by navigating to the Capture/Deform tab and pressing the Set Capture Pose button.

Creating Muscle Rigs

  1. Click the Muscle Rig tool on the Muscles shelf tab.

  2. Select the skin object to draw your stroke on and press Enter.

  3. Stroke a curve onto your skin geometry. You may stroke multiple times until you are satisfied with the placement of your muscle. Each time you draw a stroke, the muscle will be redrawn.


    While the stroke state is active, you can adjust the muscle radius using the mouse wheel, or ⇧ Shift + dragging.

  4. After a stroke has been drawn, you may adjust the depth of the drawn muscle rig relative to your skin surface by adjusting the Depth parameter.

  5. Once you are satisfied with the shape and position of the stroked curve, press the Accept Stroke or Accept and Create New Stroked Muscle button to save your stroke as the current pose. You will still be able to modify the position of the rig handles to further refine or shape your muscle.


    You can also press Enter to complete the stroke and return to object mode, or press Q to repeat the operation (which will complete the current muscle stroke and begin a new one).

For more information, the muscle workflow help page.

See also

Shelf tools

Using the shelf

  • Customize the shelf

    How to change the look of the shelf, change and rearrange its contents, and create your own shelf tools.

Shelf tabs

  • Create tab

    Tools on the Create tab let you create and place primitives, curves, and null objects in the scene view.

  • Modify tab

    Tools on the Modify tab let you easily customize objects in the scene view.

  • Model tab

    Tools on the Model tab let you edit objects in the scene view.

  • Polygon tab

    Tools on the Polygon tab let you modify polygons in the scene view.

  • Deform tab

    Tools on the Deform tab let you deform objects in the scene view.

  • Texture tab

    Tools on the Texture tab let you texture objects in the scene view.

  • Rigging tab

    The Rigging tab contains tools for creating premade rigs.

  • Muscles tab

    The Muscles tab contains tools for creating muscles.

  • Characters tab

    Tools on the Character tab let you create characters in the scene view.

  • Constraints tab

    Tools on the Constraints tab create a constraint network where you can constrain objects to each other in the scene view.

  • Hair Utils tab

    Tools on the Hair Utils tab let you quickly set up hair and fur on objects.

  • Guide Process tab

    Tools on the Guide Process tab let you influence the placement and orientation of guide hairs by painting skin attributes.

  • Guide Brushes tab

    Tools on the Grooming tab let you add and directly manipulate hair.

  • Terrain FX shelf tab

  • Cloud FX tab

    The Cloud FX tab contains tools for creating cloud effects.

  • Volume tab

    The Volume tab contains tools for creating volume effects.

  • Lights and Cameras tab

    Tools on the Lights and Cameras tab let you create and place lights and cameras in the scene view.

  • Collisions tab

    Tools on the Collisions tab let you create collision objects in the scene view.

  • Particles tab

    Tools on the Particles tab let you create dynamic particle simulations.

  • Grains tab

    The Grains tab contains tools for simulate grains of sand and other granular matter.

  • Vellum tab

    The Vellum tab contains tools for creating different types of vellum effects.

  • Rigid Bodies tab

    Tools on the Rigid Bodies tab let you create dynamic RBD objects in the scene view.

  • Particle Fluids tab

    Tools on the Particle Fluids tab let you create particle based liquids in the scene view.

  • Viscous Fluids tab

    Viscous fluids are FLIP simulations that use a temperature attribute to drive viscosity.

  • Oceans tab

    The Oceans tab contains tools for creating ocean simulations.

  • Fluid Containers tab

    The Fluid Containers tab contains tools for creating pyro, smoke, and liquid containers.

  • Populate Containers tab

    The Populate Containers tab contains tools for creating and removing fire, smoke, and liquid.

  • Container Tools tab

    The Container Tools tab contains tools for manipulating fire, smoke, and liquid.

  • Pyro FX tab

    Tools on the Pryo FX tab let you create simulated smoke and fire effects.

  • Solid tab

    Tools on the Solid tab let you create and modify solid objects.

  • Wires tab

    Tools on the Wires tab let you create flexible dynamic objects in the scene view.

  • Crowds tab

    The Crowds tab contains tools for creating crowds, crowd behaviors, as well as examples.

  • Drive Simulation tab

    Tools on the Drive Simulation tab let you manipulate dynamic objects in the scene view.