How to Use GearGen.XYZ
The Basics
1. Add a Gear
To add a gear to the current gearset press the add a gear button. The gear is added paired to the gear number before it in the set. Gear 3 and above can have the gear it meshes with edited with the driving gear selection below.
2. Add a GearTrain
To add another stage to the reduction select click here, it will create another stage with a gear in a different color with a shaft connection to the last gear in the gearset before it. The shaft connection gear can be changed.
3. Editing the Current Gear
The current gear being edited is shown by the underlined tabs in the geartrain 
and gear 
tab line.
4. Edit the Basic Gear Parameters
Gear geomtery is formed by the hob cutting tool and these are the basic parameters you need to set. Number of teeth, module for the size of the gear tooth, the pressure angle of the gear and the profile shift to set thickness of the gear tooth.
a. Number of teeth - Set the number of teeth on the gear here, type the number into the box or use the + and - buttons to increment or decrement the number of teeth. Minimum number of teeth is 10T.
b. Module - Set the module of the gear here, type the number into the box or use the + and - buttons to increment or decrement the module, it will increment by the common modules. Only Series I modules will be shown until the Ext. Series checkbox is checked, and will then show all modules including Series II.
c. Pressure Angle - Default is 20°, increment or decrement the pressure angle to change it to any of the following common pressure angles: 14.5, 15, 20, 22.5, 25, 30. Type in any other pressure angle to set it to that value.
d. Profile Shift - Set the profile shift of the gear here, type the number into the box or use the + and - buttons to increment or decrement the profile shift.The profile shift is limited in range to prevent undercutting and tooth tips that are pointed. It will prompt you telling you when you have exceeded the limits.Adjusting the profile shift will also adjust the center distance of the gearset and vice versa, so the lock button is there to prevent the value from changing when editing the center distance.Span can be entered to set the profile shift when reverse engineering.
5. Set the Gearset's Position
Edit the center distance, x and y position and the angle of the gearset with the following parameters.
a. Center Distance - Adjust the center distance of the gearset here, type the number into the box or use the + and - buttons to increment or decrement the center distance.
Adjusting the center distance will prompt how the profile distance should be adjusted. All pinion, all gear, or split. When the center distance is locked, the sum of the profile shifts stays the same so increasing one gear will decrease the other gear.
b. X - Y Position - Set the X or Y position of the gearset here, type the number into the box or use the + and - buttons to increment or decrement the X or Y position. X or Y not edited will be adjusted to keep the center distance constant.
c. Angle - Set the angle of the gearset here, type the number into the box or use the + and - buttons to increment or decrement the angle. Center distance is kept constant and X and Y are adjusted.
6. Backlash Selection
Some recommended backlashes are presented, and how they are calculated is here. Own input is available to set the backlash for each gear individually.
7. Gear Span Measurement
The span measurment is an inspection measurement of the gear tooth thickness.
The span measurement changes when the profile shift is adjusted. The profile shift will change when a span measurement is entered. This is feature relevant for the reverse engineering and inspection of gear teeth.
The number of teeth spanned is first set to the optimal number, but can be adjusted to any number of teeth within its possible range. If you pick a number of teeth outside the possible range, you will be prompted and the control will snap to the nearest valid span.
8. Download
Download the gear here. The options presented are the gear currently selected, the gearset currently selected, or all of the gears and gearsets currently in the viewer. SVG and DXF are the two options for download.