One important issue when using images for making objects is getting the aspect ratio correct. You can somewhat ignore this at the beginning but eventually you’ll start asking why straight lines are off and how to get the exact wall thickness you want. For the Image Lathe this comes down to using the right aspect ratio for your profile and pattern image. If you use the correct values then your conversion from 2D to 3D will be much more enjoyable.
Let’s start with a candle profile. I want to make the candle be 2.75″ wide and 5.25″ tall. Since we are rotating the profile image around to make the object we want to use 1/2 of the total width which is 1.375″. So we want an image 1.375″ / 5.25″ in aspect ratio(0.262). I used 198 pixels for the width so the height would be 756 pixels.
For the pattern image we need this relationship: Pwidth/Pheight = (vaseWidth/vaseHeight)*(PI/symmetryOrder).
The pattern image aspect ratio is related to the physical dimensions of the object and the symmetry order we are using. For this example I’m making the object be 2.75″ x 5.25″ and using a symmetry order of 12. If it set the width to 396 pixels then the height will need to be 2888. In reality this was way more pixels then I needed for this design so feel free to lower that.
Here is the final object created from this: