I have an image file that is designed in Cinema 4D and rendered, and to be used for logo purpose.
I want to vectorize it. I tried the "image trace" method, but it decreases quality.
Do you have any suggestion?
You can render to Illustrator (.ai as vectors) if you have the Sketch and Toon plugin. But I think it will not be easy to achieve the glossy look you showed in the rendering. There are quite some tutorials on the web how to set up S&T for this. One example would be: https://vimeo.com/143470220
Most 3D renders are raster images.
Image Trace is about the only option other than manually redrawing it.
You can try to render the image as large as possible. Larger images allow Image Trace in Illustrator to better see small details and changes.
Ultimately, for quality, the only sure-fire method is to redraw it in Illustrator unless you know of a 3D package capable of good quality vector output. Thus far, I've seen some vector output from 3D packages, mostly just splines, but the construction often leaves a lot to be desired. Making reconstruction in Illustrator more favorable. I'd imagine your goal would be to keep all those highlights and shadows not merely the paths associated with them. In my experience, that can only be done via a raster rendering.
This is a pretty common problem with no easy workarounds to completely replicate the look of a rendered logo... kind of the point of 3D rendering, that it be special.
While we await the impending and wholesale demise of the flat trends...
...HOWEVER... you can get the basic shapes out and into Adobe Illustrator, like so:
Furthermore, you can export DXF formats and open them in Illustrator.
You're getting paths this way, so you'll need to have some idea what you want to do with them once you've gotten them out. They aren't going to be anything like a rendered version.
@Scott, 3ds Max exports Splines straight to legacy formats of AI. The results aren't always nice paths, but it always works.
Most other 3D apps have some form of vector output, almost always CAD based, which can eventually be wrangled into Illustrator. Some of the better and more creative renderers have cartoon and edge drawing facilities that also output vectors.