smoke ring portal 3d model

A mysterious circular portal made entirely of dark grey smoke. The portal is perfectly round, with thick swirling smoke forming the ring. The smoke moves slowly and naturally like real drifting fog, with layered wisps and curls that twist around the circular shape. It is dense and realistic, not liquid nor cloudy or fluffy, and not geometric or boxy. The center of the portal is slightly darker, like a deep void. The smoke has subtle motion, with small tendrils breaking off and fading into the air. Lighting is dim and moody, with soft highlights on the smoke edges to emphasize depth and realism. The portal looks slightly ominous, floating in the air. Style: hyper-realistic, cinematic lighting Color: dark grey to charcoal smoke Shape: perfect circular ring of smoke Effects: swirling, drifting, volumetric smoke Environment: dark background to highlight the portal