Welcome to SolidWorks forums Deividas.
There can issue with setting up the appearance. Can you attach your file here to check.
Please use "advanced editor" in case you want to attach any files.
You might also find this post helpful for your future reference.
who can help me ? what to do? to paint new model ?
You say you are "rendering" the picture. Does this mean you are using PhotoView or are you using only the appearance choices in SWorks? Whichever you are using, pay attention to the choices in the "illumination" blocks. Play with the settings for "diffuse amount", Specular amount", "Specular spread" and "reflection amount". If you are using PhotoView the "gamma" setting can make a big difference.