Conclusion First
After comparing 9 conditions, no condition successfully reproduced a clear six-pack (6 clearly separated muscle blocks). With abs, six pack, visible abs, ab lines, defined core, and muscle definition, a tendency for faint vertical lines or shading to appear on the abdomen was observed compared to the control, but the effect showed significant variation across seeds. In seeds 2 and 3, high-waist bottoms or leggings were frequently generated, covering the abdomen.
Experimental Design
| Item | Value |
|---|---|
| Model | z-image-turbo (6B, photorealistic distilled) |
| Steps | 8 |
| Sampler | euler |
| Scheduler | ddim_uniform |
| CFG | 1.0 |
| Size | 1024x1024 |
| Seeds | 3 fixed seeds (common across all conditions) |
| Per condition | 3 images (3 seeds) |
| Total | 9 conditions = 27 images |
Base Prompt
Using sports bra + full body to observe abdominal muscle detail.
A00: control
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: All 3 images show a flat, smooth abdomen with no vertical lines, horizontal lines, or shading from ab muscles. Seed 1: sports bra + bikini bottoms with exposed abdomen. Seed 2: sports bra + cycling shorts with abdomen partially covered by high waist. Seed 3: sports bra + shorts with visible abdomen but at a more distant angle. Overall build is slim and standard.
A01: abs
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows faint central vertical line (linea alba) and light shading at the left-right rectus abdominis boundary compared to control. Not a clear six-pack, but a more toned impression than control. Seed 2 is nearly identical in composition and outfit to control s2, with only a slight addition of abdominal shading. Seed 3 shows white sports bra + high-waist shorts with no notable abdominal change.
A02: six pack
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows light abdominal shading with faintly visible rectus abdominis contours compared to control. However, not a six-pack with 6 clearly separated blocks. Seed 2 shows white sports bra + cycling shorts with only upper abdomen exposed due to high waist, with slight vertical line visible. Seed 3 is at a more distant angle, small, and abdominal detail is hard to distinguish — little difference from control s3.
A03: toned abs
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows relatively flat abdomen with almost no difference from control. The addition of toned shows no clear toning effect. Seed 2 shows white sports bra + cycling shorts with slight shading in the exposed abdominal area. Seed 3 shows sports bra + shorts with smooth abdomen and no notable muscle detail. Overall weaker effect than abs alone.
A04: visible abs
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows central vertical line and light shading at left-right ab block boundaries. Similar effect to abs alone. Seed 2 shows sports bra + half pants with high waist covering most of the abdomen. Seed 3 is at a distance and abdomen appears smooth. Adding visible shows no clear improvement over abs alone.
A05: washboard
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows faint abdominal shading with visible rectus abdominis boundary lines. Slightly more toned impression than control but not dramatic. Seed 2 shows sports bra + full-length leggings with abdomen completely covered by high waist. Seed 3 also has abdomen covered by high-waist bottoms. washboard was intended to mean “washboard abs,” but the prominent side effect of clothing covering the abdomen is notable.
A06: ab lines
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows a clearly visible central vertical line (linea alba) and faint left-right rectus abdominis boundaries. One of the cases with the most visible “lines” in this experiment.
Note: Seed 1 shows faint vertical lines, but not clearly defined enough to read as a six-pack. Seed 2 shows sports bra + leggings with only the upper abdomen exposed and slight shading. Seed 3 is at a distance and the subject is turned sideways, making the front of the abdomen hard to see.
A07: defined core
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows vertical lines and rectus abdominis shading comparable to ab lines detail. Slight oblique (external oblique) shading also visible. Seed 2 shows white sports bra + cycling shorts with faint vertical line in the exposed abdominal area. Seed 3 shows sports bra + shorts at a distance, abdominal detail difficult to distinguish.
A08: muscle definition
| seed 1 | seed 2 | seed 3 |
|---|---|---|
 |  |  |
Observation: Seed 1 shows faint vertical lines and abdominal shading with a toned body type. Similar effect to abs and defined core. muscle definition is expected to apply body-wide rather than just to the abdomen, but the abdominal effect is not notably different from other keywords.
Summary
Effect on Abdominal Detail
| Condition | Abs Lines/Shading | Six-Pack | Side Effects |
|---|---|---|---|
| control | None | None | — |
| abs | Faint | None | Few |
| six pack | Faint | None | Few |
| toned abs | Almost none | None | Few |
| visible abs | Faint | None | Few |
| washboard | Faint | None | High-waist clothing tends to cover abdomen |
| ab lines | Faint to weak | None | Few |
| defined core | Faint to weak | None | Few |
| muscle definition | Faint | None | Few |
Findings and Notes
No six-pack was produced. Across all 9 conditions, not a single image showed a six-pack with 6 clearly separated muscle blocks. What was obtained was at most a faint linea alba or barely-visible rectus abdominis boundary shading — far from the abs detail of a fitness model.
The effect depends heavily on seed. In seed 1 (sports bra + bikini bottom composition), faint ab shading was observed across most conditions. Seeds 2 and 3 frequently generated high-waist cycling shorts or leggings, covering the abdomen and making the effect impossible to evaluate.
Outfit side effects. Particularly with washboard, seeds 2 and 3 generated full-length leggings or high-waist bottoms, making observation of the abdomen itself difficult. Ab keywords may strengthen associations with fitness wear overall.
Recommendation. If you want to express abs, abs or ab lines are the simplest with the fewest side effects. However the effect is weak — if you’re aiming for a clear six-pack, an approach that changes the whole body type (such as muscular or athletic build) or alternative methods like ControlNet may be worth considering.
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