XS_ZOOM_STEP_RATIO_IN_MOUSEWHEEL_MODE
Category in Advanced options dialog: Model views
Use this advanced option to set the zoom ratio
when you are zooming by scrolling the middle mouse button. Enter a decimal value. To
zoom more with a single mouse scroll notch, increase the value. The default value is
0.05.
This advanced option is user specific and the setting is saved in options.bin under the user folder, for example, in C:\Users\<user>\AppData\Local\Trimble\Tekla Structures\<version>\UserSettings. Restart Tekla Structures to activate the new value.