You are! If you upload and order something and afterward offer it for sale, you retain all the intellectual property rights (IPRs) to your 3D design. By accepting the vendor terms and conditions, you give i.materialise the right to produce copies of the model in return for a designer's fee (also known as markup).
Please note that by uploading your 3D design, you confirm that you are the owner and/or you have obtained from a third party the rights necessary for submitting this order to i.materialise for production and commercial use without any violation of any intellectual property rights.
For more information, please see our Terms and Conditions regarding Intellectual Property.