An example of a rendered SketchUp model from my garden design days – SketchUp image on right, photo of finished product on left.
The whole project was done on SketchUp – and paper, because I’m a graphite sort of s guy – planters and trellis were sent off for CNCing directly from the model, metalwork was designed and turned into measured drawings for fabrication, and pretty pictures were available for the client.
At the time it was pretty extraordinary to get that much power from software that was free generally, and cost only a few £hundred for the professional version plus a rendering plugin. Also: relatively shallow learning curve, and relatively quick to create with. I’m not an expert with it, but could always get presentable enough results. It’s unforgiving in many ways though, and non-parametric, As @Twm said, working in mm always worked out accurately for me, though I think there may have been a bit of rounding somewhere along the line?