If I sketch a simple spiral and then scan it in as a JPG from my printer, how do I extrude that to make it into a 3D model. I imported the JPG, but it just brings in the entire sheet of paper with the spiral drawn on it. I’ve read several tutorials that seem to be around this topic, but really can’t seem to crack the code. (my application will be more complicated, hence why I don’t just draw it in SketchUp to begin with)
A jpg file is only a raster image. There’s no vector information in it from which to create edges. There are a couple of extensions that you might use. The first is TIG’s Image Trimmer. It requires a PNG image with transparent pixels instead of a white background. The extension is available from Sketchucation. Another one is BMP Tracer which requires a bmp file. See this post. In both cases you may find that the resulting geometry has been simplified more than you want or is rougher due to pixelation in your original image. But you can give them a try.