﻿ Getting Started Tutorials - MechDesigner > Tutorial 15: Patterns - Indexing-Chain example > Step 15.1: Piggyback Sliders

# Step 15.1: Piggyback Sliders

### Piggyback Sliders to model the Path of a Point on the Belt

We must model the motion of a point on the path of a Belt.

To do this, we design two motions for the Point: its X-axis and Y-axis motion components.

We give the each motion to a different Slider. We configure the two sliders as 'Piggyback Sliders'.

When we cycle, the Y-axis Slider moves in the Y-axis direction. The Y-axis Slider is being carried by the X-axis Slider. Thus, the Point also move in the X-axis direction.

If we design the motions correctly, the Point on the Y-axis Slider has the same motion as a Point on a Belt.

In this Tutorial Step, we add a set of Piggyback Sliders. We call the two Sliders a Slider Set.

We design the two motions for Slider-X and Slider-Y in Tutorial Step 15.2.

Note - From Release 11+, it is often to use a sketch-loop and Motion-Path FB. See Tutorial 11.

However, we should learn how we go about the model the piggyback sliders, as it is an important modeling method.

#### How do we add Piggyback Sliders? Short Version.

 We add the Piggyback Sliders as follows: •Add a Slider to move parallel to the X-axis of the Base-Part. We name it Slider-X•Edit Slider X to add vertical Line, usually along the Y-axis of Slider X.•Add another Slider to the new Line in Slider-X to move along the Y-axis of Slider-X. We name it Slider-Y. A Point, called Point-XY, is a child to the Slider-Y. The movement of the Piggyback Sliders and the Point XY, is as follows: •If only Slider-X moves, then Point-XY moves along the X-axis of the Mechanism-Plane, (or the Part Plane of the Part to which we join Slider-X).•If only Slider-Y moves, then Point-XY moves along the Y-axis of the Mechanism-Plane, (or the Part Plane of the Part to which we join Slider-X).•If Slider-X and Slider-Y move, then Point-XY moves with the combined movement in the Mechanism-Plane (or the Part Plane of the Part to which we join Slider-X).