Put vanilla wafers in food processor and pulse until finely chopped.
Add 3/4 cup sugar and melted butter and pulse to incorporate.
Grease bottom and sides of 9" spring form pan.
Press mixture into bottom and slightly up sides of pan.
Place in freezer for 30 minutes.
Beat cream cheese and remaining sugar until smooth.
In a medium bowl, combine gelatin and boiling water. Whisk until dissolved.
Zest orange and set aside.
Whip heavy cream, powdered sugar and vanilla until stiff peaks form.
Add 1/2 of whipped cream mixture to cooled gelatin and add orange zest. Whisk to blend. Set aside.
Fold remainder of whipped cream mixture into cream cheese mixture.
Spread 1/2 cream cheese mixture over crust.
Pour 2 cups of orange whipped cream mixture over cream cheese mixture.
Gently spread remaining cream cheese mixture over orange mixture.
Pour remaining orange whipped cream mixture over cream cheese mixture.
If desired, take a butter knife and gently glide through cream cheese layers to swirl.
Refrigerate for at least 6 hours.