Architectural illustrators should generally sign their renderings

Architectural illustrators should generally sign their renderings to help them feel valued and recognized for their work, establish authorship, protect intellectual property, and build professional branding. The signature should be discreet, avoiding any overshadowing of the artwork. While not legally required like an architect's seal, a signature acts as a copyright mark to prevent unauthorized usage. It distinguishes the artist's work, aids in marketing, and maintains a professional, artistic standard. 

Key considerations for signing renderings include:

Visibility: Place the signature in a corner or a location that does not distract from the architectural design, often subtly integrated into the image, such as on a sidewalk or in a shadow. This helps illustrators feel confident that their signature can be discreet yet effective, respecting the artwork's integrity. Purpose: Signing highlights the specific artistic contribution, which is distinct from the legal, technical, and liability responsibilities of an architect's stamp.

Professional Branding: For freelance illustrators, signing their work is a key way to ensure they are credited for their contributions when their work is shared or published, boosting their confidence and supporting their branding efforts and portfolio development.While some clients may request no signature for a clean, "finished" photo-real look, signing is generally accepted industry practice for artistic work.