how do I keep an object in the world but stop it from rendering to reduce lag. And if you cant stop Greenfoot from rendering an image would changing the alpha to 0 reduce lag.
How about changing its image to 'new GreenfootImage(1, 1)'. I do not think that changing alpha to zero would help much, or at least noticeably, if at all. The system would still have to iterate through all the pixels, regardless.