# build()

Full build, same work as the Build button. An empty scene is fine. The biped is created with the rig. Returns `rig`. Failure raises `RuntimeError`.

### Signature
```python
api.build(**params) -> rig
```

The usual call:

```python
rig = api.build(height_cm=170, engine_type="unreal")
```

Omitted values use these defaults.

| Argument | Default | Meaning |
|------|------|------|
| `engine_type` | `"unreal"` | `"unreal"` or `"unity"` |
| `biped_style` | `"human"` | Biped style |
| `height_cm` | `170` | Height in cm. `<= 0` is `ValueError`. `True`/`False` is `TypeError` |
| `spine_count` | `3` | Spine links |
| `neck_count` | `1` | Neck links |
| `leg_links` | `3` | Leg links. `4` is a reverse leg. Double Knee stays 3 |
| `arm_twist_seg` | `3` | Arm seg, 1–5 |
| `leg_twist_seg` | `3` | Leg seg. Double Knee is 2, 3, or 5 |
| `fingers` | `5` | Finger count |
| `finger_links` | `3` | Finger links |
| `double_knee` | `False` | Double Knee. `True` requires `knee_type` `"None"` |
| `hip_type` | `"None"` | Hip extra |
| `tail_type` | `"None"` | Tail |
| `knee_type` | `"None"` | Calf corrective. Conflicts with Double Knee |
| `elbow_type` | `"None"` | Elbow corrective |
| `upperarm_type` | `"None"` | Upper-arm corrective |
| `prop_1` `prop_2` `prop_3` | `False` | Props. Must be `True`/`False` |
| `create_rig_info` | `True` | Create the INFO node |
| `com` | none | Biped name when more than one biped is already in the scene |

On/off values must be `True` or `False`. Unknown names raise `TypeError`. A reverse leg is `leg_links=4`. There is no `horse_link` argument.

### Two or more bipeds

If the scene already has more than one biped, pass `com="Bip001"` or select the biped first. Otherwise `ValueError`.

### Double Knee

```python
rig = api.build(height_cm=170, leg_twist_seg=5, double_knee=True)
```

`leg_twist_seg` must be 2, 3, or 5. 4 stops the build.

### Example
```python
from os_bipedPlus import openAPI

api = openAPI()
rig = api.build(height_cm=165, engine_type="unity", spine_count=4)
print(rig.com)
```

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