> For the complete documentation index, see [llms.txt](https://docs.deepform.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.deepform.net/explorations/start-exploration/geometry-processing-errors/no-objects-above-grade-error.md).
# No Objects Above Grade Error
We consider ground level to be at Z 0.0 elevation. There must be objects whos lowest point is or above that elevation for us to calculate the buildings Site Coverage Area. Please ensure your models ground level is at that elevation.
Sometimes your model might seem like it is at the right level, but your CPlane might be modified. To check, you can try:
* Restore the CPlane to its original position by using the `CPlane` command, with the `World`, then `Top` options.
* If your restored CPlane seems to be above the model, change your model's elevation using the `Move` command with `Vertical` option.
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