Copyright Goodheart-Willcox Co., Inc. Chapter 10 Advanced Surface Modeling 251 The Expression option allows you to enter an expression to constrain the offset distance. Surface associativity must be enabled in order to use this option. Exercise 10-5 www.g-wlearning.com/CAD/ Complete the exercise on the companion website. Creating Fillet Surfaces The SURFFILLET command is used to create a fi llet between two existing surfaces. The fi llet created is a rounded surface that is tangent to the existing surfaces. You can create fi llet surfaces from existing surfaces or regions. The existing objects do not have to intersect. Using the SURFFILLET command is similar to using other fi llet commands in AutoCAD. Commands used to fi llet solids are introduced in Chapter 8. To create a fi llet surface, select the SURFFILLET command. First, set a radius using the Radius option. Then, select two surfaces. AutoCAD stores the radius you specify as the setting for the FILLETRAD3D system variable. If you do not specify a radius, the current FILLETRAD3D system variable setting is used. SURFFILLET Ribbon Surface Edit Surface Fillet Type SURFFILLET A B C Arrows indicate offset direction B A Figure 10-17. Using the SURFOFFSET command. A—After selecting the surface to offset, offset arrows are displayed to indicate the direction of the offset. B—The surface is offset to the inside of the hair dryer housing at a distance of .125. C—The Solid option is used to create a new solid using the specified offset distance from the base surface. Figure 10-18. The Connect option of the SURFOFFSET command is used to maintain the connection between surfaces when offsetting multiple surfaces. A—The original model. B—The vertical surfaces are offset using the Connect option.