Manual Input
Set your own parameters with sliders
Overview
Manual Input mode lets you control every parameter directly using sliders. This is useful for:
- Testing “what if” scenarios (e.g., what happens if I add 200 rpm of backspin?)
- Understanding how each parameter affects trajectory
- Entering data from sources other than Statcast or Rapsodo
Parameters
| Slider | Range | Description |
|---|---|---|
| Speed | 100–170 km/h | Release speed |
| Backspin | −3000 to 3000 rpm | Backspin component (negative = topspin) |
| Sidespin | −3000 to 3000 rpm | Sidespin component |
| Gyrospin | −3000 to 3000 rpm | Gyrospin component |
| Vert angle (θ) | −10° to 10° | Vertical release angle |
| Horiz angle (φ) | −10° to 10° | Horizontal release angle |
Click Simulate to run the physics simulation with these values.
Advanced Options
Below the spin sliders, additional controls are available:
| Control | Description |
|---|---|
| CL Model | Lift coefficient model: Nathan 2020 (exp) (default) or Rational (old). See Statcast Mode — Physics Model Options for details. |
| Fixed Cd | Override the drag coefficient with a constant value (leave blank for the Nathan speed-dependent model) |
| Fixed Cl | Override the lift coefficient with a constant value (leave blank for the model-based calculation) |
Release Position
The release position (x₀, y₀, z₀) is set based on the most recent Statcast pitch or the default values:
- x₀ = pitcher’s lateral offset (R: −0.47m, L: +0.47m)
- y₀ = 16.764m (55 ft from home plate — standard release distance)
- z₀ = 1.50m (approximate release height)
When using Rapsodo mode, the release position updates automatically.
Experimenting
Changing one thing at a time
The best way to learn what each parameter does:
- Start with a typical fastball (speed 150, backspin 2200, sidespin 0, gyrospin 0)
- Hit Simulate
- Change one slider (e.g., add 500 rpm sidespin)
- Turn on Overlay, hit Simulate again
- Compare the two trajectories
Quick presets to try
| Preset | Speed | BS | SS | GS | θ | φ |
|---|---|---|---|---|---|---|
| Four-seam fastball | 155 | 2200 | 200 | 0 | −1 | 2 |
| Curveball | 125 | −2000 | 800 | 0 | 2 | 1 |
| Slider | 135 | 200 | 1800 | 1000 | 0 | 1 |
| Changeup | 140 | 1400 | 400 | 0 | −1 | 2 |
| Gyro slider | 135 | 100 | 500 | 2000 | 0 | 1 |
Note
These are rough approximations. Every pitcher is different — that’s what makes Statcast mode valuable.