Attribute Holder Modifier

The Attribute Holder modifier is an empty modifier that provides a readily accessible user interface on the Modify panel to which you can add custom attributes. It has no user interface of its own; the interface consists solely of those attributes you assign to it. In essence, Attribute Holder is a stripped-down version of Parameter Collector that can collect only custom attributes and appears on the Modify panel instead of a floating dialog.

• Create or select an object. > Modify panel > Modifier List > Object Space Modifiers > Attribute Holder
• Create or select an object > Modifiers menu > Animation > Attribute Holder

Procedures

Example: To collect different custom attributes in an Attribute Holder modifier:

Before undertaking this procedure, you should be familiar with basic usage of the Parameter Wiring dialog.

1. Add a small box to an empty scene. Make it about 20.0 units on a side.
2. Apply a Taper modifier and an Attribute Holder modifier, in that order.

   In the modifier stack, the Attribute Holder modifier should be highlighted.

3. From the Animation menu, choose Parameter Editor.
4. In Parameter Editor, on the Attribute Rollout, make or ensure the following settings:
   • Add to Type=Selected Object's Current Modifier
   • Parameter Type=Float
   • UI Type=Slider
   • Name=Box Height
5. On the Float UI Options rollout, keep all the default settings.
6. On the Attribute Rollout, click Add.

   The Custom Attributes rollout appears on the Modify panel, containing the new Box Height slider.

7. Add another attribute:
   • Add to Type=Selected Object's Current Modifier
   • Parameter Type=Integer
   • UI Type=Spinner
   • Name=Box Height Segs
   • Integer UI Options Range=From 1 to 50.
8. Add two more Float/Spinner attributes named Taper Amount and Taper Curve.

   The Attribute Holder modifier now has four custom attributes, but they don't do anything because they're not connected. You'll use Parameter Wiring to hook them up.

9. Close the Parameter Editor dialog.
10. In the active viewport, right-click the box and choose Wire Parameters. From the pop-up menu that appears, choose Modified Object Box (Object) Height.

    A rubber-band dashed line appears connecting the mouse cursor to the box.

11. You can't connect this “wire” directly to the custom attribute, so just left-click in an empty part of the viewport to open the Parameter Wiring dialog.

    The hierarchy list on the left side, Box01, is expanded to the box's Height parameter, which is highlighted.

12. On the right side, expand this path: Object Box01 Modified Object Attribute Holder Custom Attributes, and then click Box Height to highlight it.
13. Click (Two-way Connection, the double-headed arrow), and then click Connect.
14. Similarly, connect Height Segments on the left side to Box Height Segments on the right.
15. Close the Parameter Wiring dialog.
16. Right-click the box again, choose Parameter Wiring, choose Modified Object Taper Amount, and then left-click to open the Parameter Wiring dialog.

    The Amount parameter is highlighted on the left side of the dialog.

17. On the right side, click the Attribute Holder's Taper Amount parameter, and then connect them.
18. Connect Curvature on the left side to Taper Curve on the right side, and then close the dialog.

    All the parameters are now hooked up.

19. Experiment with changing the values on the Custom Attributes rollout.

    The Attribute Holder modifier lets you change the box's creation parameters as well as the Taper modifier's settings without switching back and forth in the modifier stack. In this way you can access, in one convenient location, as many different parameters from different levels in an object's modifier stack, or even from different objects, as you like.

    You might notice that you can't set the taper to curve inward. You can resolve this by reopening Parameter Editor, clicking Edit/Delete, and then modifying the Taper Curve attribute to allow negative values. The change takes effect immediately, with no rewiring required.