Welcome aboard!

There is indeed a special treatment when zooming in:

```
delta = this.computeDeltaFromMouseWheelLegacyEvent(wheelDelta, this.camera.radius);
// If zooming in, estimate the target radius and use that to compute the delta for inertia
// this will stop multiple scroll events zooming in from adding too much inertia
if (delta > 0) {
var estimatedTargetRadius = this.camera.radius;
var targetInertia = this.camera.inertialRadiusOffset + delta;
for (var i = 0; i < 20 && Math.abs(targetInertia) > 0.001; i++) {
estimatedTargetRadius -= targetInertia;
targetInertia *= this.camera.inertia;
}
estimatedTargetRadius = Scalar.Clamp(estimatedTargetRadius, 0, Number.MAX_VALUE);
delta = this.computeDeltaFromMouseWheelLegacyEvent(wheelDelta, estimatedTargetRadius);
}
```

I don’t know however if that is expected that the speed is different when zooming in vs zooming out… Note that if you use `wheelDeltaPercentage=0.01`

for eg, the speed will be the same (at least visually)…