Checking an AI render against your design
What a second system can check when an AI render comes back, what it cannot, what is left to your own eye, and how the answer is recorded in a signed Render Receipt.
In the beta today: Ply’s render engine and Vel’s review are still being finished. Until they land, a render in the beta returns your source image unchanged, and Vel is a stand-in reviewer that answers from a fixed script: its decisions there say nothing about the image. Credits there are test credits.
Why a second system checks the first
The system that made a render should not be the only one to judge it. Plyvel splits the two jobs. Ply makes every change. Vel only reviews: it compares the result with the approved source and your request, and it never edits the image.
Vel reviews Verified Renders and Portfolio Renders. A Ply Draft or a Targeted Edit is not reviewed, and is marked NOT VEL VERIFIED.
What Vel compares, and how it answers
Vel compares the result with the approved source and with your request: the requested change, and each element you kept, such as the camera, the massing and the openings. It also looks for artefacts, such as a smear or a repeated detail.
It answers PASS, FIX or UNCERTAIN. On FIX, Ply corrects the render once against the approved source, at no extra cost, and Vel reviews again.
| How a reviewed render ends | What it means |
|---|---|
| VEL VERIFIED | Vel answered PASS on what it compared. |
| VERIFICATION UNCERTAIN | Vel could not decide. The render is not charged, and it never becomes a pass by itself. |
| ACCEPTED WITH FINDINGS | You accepted an uncertain result as it is. It is always written out in full, and never shown in the green of VEL VERIFIED. |
| VERIFICATION FAILED | Vel still found problems after the included correction. Its credits are released in full, and it still gets a receipt. |
In the app’s Help: Vel’s review and its outcomes
What it cannot see
- Visual, not certification. Vel compares images. Its checks are not measurements, and they do not cover structure, building codes, construction or dimensions.
- Hidden parts. Where a tree, a shadow or another object hides part of the building, Vel can flag a problem that is not there. When it is not sure, it answers UNCERTAIN.
- Small things. A small change in a busy area, or a detail at the edge of the frame, can pass. A fine element, such as one post of a balustrade, can be missed.
Known limits lists the rest, in the beta and after it.
In the app’s Help: What Vel cannot certify
Your own check comes last
Compare every result with the approved source yourself: Slider, Side by side, Blink, Difference, or the result alone. Difference shows the result in grey with every changed pixel in red. It is not a geometry check, and it is not Vel’s review.
Approving is a person’s decision: this is the result you keep. It is recorded with who approved it and when, beside the receipt, and it never changes what Vel found. For anything that will be built or set out, use the drawings and the review of a qualified professional.
In the app’s Help: Comparing a result
The record: a Render Receipt
Every completed render gets a Render Receipt: the state, the request, what was kept, what could vary, Vel’s review, the attempts and when it was issued. It is signed with Plyvel’s key.
Check the signature checks it in your browser against Plyvel’s published public keys. Check the file computes the image’s SHA-256 and compares it with the receipt. The signature shows that the record is unchanged since Plyvel issued it. It does not show that the design is right.
A receipt, not a certificate. This receipt records Plyvel’s visual checks. It is not structural, engineering, building-code, construction, or dimensional certification.
In the app’s Help: Reading the Render Receipt
Updated 18 October 2026.