# Gemini Iteration Prompt — fix the v2 errors and re-render

This is a follow-up prompt to give Gemini after running the v2 prompt. It assumes you've already generated one image with the v2 prompt and you're giving Gemini the v2 result back as a "before" image, alongside the corrections.

**How to use it:** In Gemini, upload TWO images:
1. Your original backyard photo (the reference)
2. The v2 Gemini rendering (the "before" with errors)

Then paste the prompt below. Gemini will use both as context to fix the specific errors.

---

## The iteration prompt (paste this)

```
The previous image you generated was almost right but had these
specific errors. Please generate a corrected version that fixes
each one.

CORRECT (keep these in the new version):
- Three redwood 4x4 posts in a single line on the side AWAY from
  the existing pavilion. NOT four posts.
- 4x4 posts (3.5" actual thickness), not 6x6. The existing
  pavilion has 6x6 posts — your new posts should be NOTICEABLY
  THINNER than the pavilion's.
- Roof slopes UP toward the existing pavilion.
- Knee braces at every post-beam joint.
- Decorative black metal post bases (with a 1-inch standoff
  between the post bottom and the concrete).

INCORRECT (fix these in the new version):
1. RAFTER DIRECTION: Your previous image had the rafters running
   parallel to the existing pavilion's beam. They need to run
   PERPENDICULAR to the existing pavilion's beam — going FROM
   the new front beam UP TO the existing 4x12 beam face. The
   rafters should look like 9 long lines crossing the width of
   the structure, each line going from low at the front to high
   at the pavilion.

2. RAFTER TERMINATION: Your previous image added a NEW horizontal
   beam in front of the existing 4x12, with the rafters sitting
   on that new beam. The correct connection is: the rafters
   attach DIRECTLY to the FACE of the existing 4x12 via a
   black metal joist hanger (Simpson LSSJ26 style). NO new beam
   in front of the 4x12. The rafters just butt up against the
   4x12 with a small metal connector visible.

3. NO PURLINS: Your previous image had horizontal purlins running
   across the rafters. The correct design has NO purlins — the
   polycarbonate panels sit directly on the rafters.

ADD THESE NEW DETAILS:
4. RAFTER TAIL OVERHANG: The rafters should extend 2 FEET past
   the new front beam as exposed wood. This is a deliberate
   decorative feature. The exposed tail should be visible in
   the new image as a horizontal shadow line / shadow gap.

5. TINTED GRAY PANELS: The roof panels should be TINTED GRAY
   (a dark translucent gray color, not clear, not silver, not
   galvanized metal). The color is similar to charcoal gray
   with some translucency — you should be able to see a faint
   hint of the rafter lines through the panels but the overall
   impression is dark gray.

6. TINTED GRAY CORRUGATED POLYCARBONATE, not metal. The panels
   have visible CORRUGATIONS (ridges running perpendicular to
   the rafters, parallel to the front beam). The material is
   polycarbonate plastic, not metal sheeting.

Other things to keep the same as the previous version:
- Same camera angle and lighting as the original backyard photo
- Same craftsman style matching the existing pavilion
- Same horizontal sandwich beams across the top of the three
  posts (pair of 2x8 boards, one front of post and one back)
- Same knee braces (45-degree mitered triangular blocks)
- Same decorative black post bases

Generate the corrected version.
```

---

## What this prompt does differently from v2

The v2 prompt was a "from scratch" description. This iteration prompt is a "diff" — it lists what was right, what was wrong, and what to add. AI image models respond well to diffs because they have a clear reference for what to change and what to preserve.

The specific Gemini failure modes I called out:
1. **Rafter direction** — the most important error to fix, since wrong rafter direction makes the structure not a lean-to at all
2. **Rafter termination** — the "added beam in front of 4×12" mistake, which I phrased as "use a Simpson LSSJ26 joist hanger" so the model has a concrete pattern to match
3. **Purlins** — Gemini invented these, you didn't ask for them
4. **2' rafter tail** — a new detail from your spec that didn't make it into the v2 prompt
5. **Tinted gray color** — Gemini rendered this as galvanized metal, not translucent gray polycarbonate

**One caveat:** Gemini might still struggle with the LSSJ26 connection. If it does, fall back to my recommendation from PROMPT-v2.md: use Adobe Photoshop's Generative Fill with a manual mask. Inpainting models respect the existing 4×12 in the photo and won't try to add a beam in front of it.

**File location:** https://pergola.aidalee.com/renderings/PROMPT-GEMINI-ITERATE.md