# CAD Constraints First Sketch

Use constraints and dimensions to make a sketch editable instead of fragile.

## Outcome
Create a simple sketch that survives later changes.

## Safe first step
Define the design intent before adding every dimension.

## Ladder steps
### 1. Name the part purpose
Learn to name the part purpose as one discrete move in the project path.

Check: You can explain or demonstrate: name the part purpose.

### 2. Anchor one reference
Learn to anchor one reference as one discrete move in the project path.

Check: You can explain or demonstrate: anchor one reference.

### 3. Apply geometric constraints
Learn to apply geometric constraints as one discrete move in the project path.

Check: You can explain or demonstrate: apply geometric constraints.

### 4. Add driving dimensions
Learn to add driving dimensions as one discrete move in the project path.

Check: You can explain or demonstrate: add driving dimensions.

## Examples
### Practice horizontal constraint
```sh
Horizontal constraint
```
Expected signal: A visible result you can compare before moving on

### Practice coincident constraint
```sh
Coincident constraint
```
Expected signal: A visible result you can compare before moving on

### Practice one driving width dimension
```sh
One driving width dimension
```
Expected signal: A visible result you can compare before moving on

## Common traps
- Fully dimensioning random geometry.
- Using tiny line offsets instead of constraints.
- Drawing final detail before the main shape is stable.

## Practice task
Create a small practice case for cad constraints first sketch and write what each step proves before moving to the next one.

## Next steps
- Download the Obsidian note.
- Review the Anki cards.
- Pick one related ladder and do the practice task.

## Related
- [Browse topic clusters](/topics/)
- [All learning ladders](/learn/)