Using the integrated bitmap tracer
dtpblender features a quite capable bitmap tracer (vectorizer) which can convert simple images, logos, etc. into vectors (curves) automatically.
It detects seperate shapes in the image and will trace them into seperate curves. It also automatically assigns appropriate materials to them, so tracing a complex multi-color logo can be as simple as 3 mouse clicks.
For tracing the individual b/w bitmaps, it uses the excellent potrace library.
Note: Although the tracer is primarily intended for tracing simple logos, characters etc., it can also be used in a more "artistic" manner, for example by tracing photos.
Let's trace this logo as an example (right-click to save):
Note that this image is very sub-optimal for tracing, because it is 1) Anti-aliased (which is bad because the boundaries aren't that clear and tight, and 2) contains overlapping objects, where the tracer of course can't "guess" what is behind the objects.
Anyway, fire up DTPBlender, SPACE, Add->DTP->Image, F6, Load Image, locate the file. Then press "Trace". You will get a "Find Regions" button with a "Tolerance" setting set to 8. Leave it that way, and click "Find Regions"!
"Find Regions" now detected all the different regions (well, colours really) in the source image, and displays their dominant colours, sorted by area from left to right. It tries to "intelligently" choose which of the regions you want to trace (those which you want to trace should have the "T" button activated).
Because the source image is anti-aliased, there are lots of different shades of the main colours (at the borders of shapes), which you obviously don't want to trace - fortunately, dtpblender turns them off automatically in most cases :)
You can see that the main 3 colours (the red, the grey of the background copy of the logo, and the grey of the border) got detected correctly. Now, of course, we don't want to trace the background (white) - so, turn it off.
Now, press Trace!
Try pressing G in the view - and say hello to your new nicely traced logo!
(Image showing one of the objects in editmode)
Note: dtpblender automatically selects all resulting objects from the trace operation, so you can instantly move/group them, or erase them again if you aren't satisfied with the result and make another attempt.
You will notice that there are small white gaps where the different shapes meet. Well, that's unavoidable - it's a result of the anti-aliasing of the source image. Using a higher "Tolerance" level (for "Find regions", not for the tracer itself) can give better results here.
The various settings in the "Trace" section are better described on the potrace homepage.
The "Tolerance" setting
A few words on the Tolerance setting for "Find regions":
This setting determines how different 2 colours can be to be still considered "equal". For example, if you want to trace photos (which is very well possible with dtpblender), you should choose a very high tolerance (around 50-100 or higher) so that you get fewer seperate colors/regions. Only the 10 biggest regions of any image can be used for tracing.
Note: When tracing complex images, it can be useful to reorder the layers of the tracing result (GZ), because sometimes, there may be overlapping areas so that layers obscure parts of each other. It is best to experiment a bit.
The following image shows a photo along with the traced result, and the individual layers of the trace:
