We present an image guided pen-based suggestive interface for sketching 3D wireframe models. Rather than starting from a blank canvas, existing 2D images of similar objects serve as a guide to the user. Image based filters enable attraction, smoothing, and resampling of input curves, and allows for their selective application using pinning and gluing techniques. New input strokes also invoke suggestions of relevant geometry that can be used, reducing the need to explicitly draw all parts of the new model. All suggestions appear in-place with the model being built, in the user's focal attention space. A curve matching algorithm seamlessly augments basic suggestions with more complex ones from a database populated with previously used geometry. The interface also incorporates gestural command input, and interaction techniques for camera controls that enable smooth transitions between orthographic and perspective views. Categories and Subject Descriptors: I.3.6 [Computer Graphics]: ...