Anim Curves

The Anim Curves panel displays curve values for Morph Target, Attribute, and Material curves for the selected skeleton. You can delete and rename curves here, as well as preview curve data. You can filter the visible curves to show only active curves by clicking on All Curves to deselect it, which also enables you to filter by Morph Target, Attribute, and Material curves with checkboxes. In addition, you can define Material Curves which enable you to drive Material Parameters or Morph Curves.

To open the Anim Curves panel in either the Skeleton Editor or Animation Editor:

  • Click on the Window menu, then select Anim Curves from the dropdown menu.

By default, as you play an animation back, the curve values will update along with the playback. In the image below, curves for L_smile_pose and R_smile_pose are being used to create a smile on the face mesh. The values of these curves are shown in the Anim Curves panel at the current point in the animation (where the full smile is achieved by being weighted at 1.0 when reaching the end of the animation).

If you uncheck the Auto checkbox for a particular curve, it will no longer pull data from the curve. This allows you to selectively turn off the influence of a curve and preview the result. You can also enter a value manually or by clicking and dragging on the Weight field. In the below image, the L_brow_up_pose curve value has been manually set to 1.0. You can see the effect in the viewport, as the left eyebrow of the face is raised all the way.

Managing Curves

To rename a curve:

  1. Right-click on the curve and select Rename from the dropdown menu.

  2. Enter your new name.

  3. Press Enter to save your new name.

To add a curve:

  1. Right-click on any curve and select Add from the dropdown menu.

  2. Enter your new curve's name.

  3. Press Enter to save your new name.

This adds a curve to the current skeleton, but you will need to then add the curve and set its information in the Animation Editor to determine what the curve affects.

To delete a curve:

  1. Right-click on the curve and select Delete from the dropdown menu.

    If the curve is currently being used by any assets in your project, a confirmation window will appear warning you that the curves will be removed from those assets.

  2. Click Yes to continue with the deletion, or No to cancel.

Linking Curves to Bones

You can link your Animation Curves to a specific bone in the Skeleton so that they can be culled out with the bone when changing Levels of Detail (LOD) for the Skeletal Mesh, which is useful when setting up facial animations that aren't needed for lower LODs. This feature can also be used in conjunction with layer blending to prevent overriding curve values from the incorrect layer.

  1. In the Anim Curves viewer window, select the curve that you want to link to a particular bone in your Skeleton.

    AnimCurveViewer_CurveSelected.png
  2. With the curve selected, in the Details panel, click the add (+) button to add Connected Bone(s) elements.

    DetailsPanel_AddConnectedBone.png

    Then use the dropdown next to the added bone, to select the bone you want to link to the curve. The list here will be populated based on the Skeleton's bone heirarchy.

    DP_SelectBones.png
  3. Now that your curve is assigned to the bone(s) you've added to the Connected Bones, you can move the camera towards or away from the mesh to see the linked curves cull from view when the LOD of the mesh changes.

Curves inside Animation Blueprints

Inside the AnimGraph of an Animation Blueprint, there are some Blueprint functions you can call to access information about or retrieve the names of your curves. 

GetCurves-1.png

Function

Description

Get All Curve Names This targets an Anim Instance and returns all curve names.
Get Active Curve Names This targets an Anim Instance and returns the last up-to-date list of active curve names for the specified Curve Type.
Get Curve Value This targets an Anim Instance and returns the value of a specified Curve Name.