---
title: "Drawing and Adjusting Roof Areas to Scale"
url: "https://eturnity.productfruits.help/en/article/drawing-and-adjusting-roof-areas-to-scale"
language: "en"
last_updated: "2025-11-10T14:06:13.647Z"
---

# Drawing and Adjusting Roof Areas to Scale

Learn how to implement precise measurements from the customer's on-site visit in Eturnity Expert. This article shows you two proven methods: quick measurement adjustment with the move tool and precise drawing with the calculator for projected lengths. Perfect for creating final offers after roof measurement.

## Why Drawing to Scale is Important

In the typical sales process, you first create a preliminary offer based only on the satellite image. After the on-site visit with the customer, you have then taken precise measurements from the roof and need to integrate these into your planning.

**The typical workflow:**

1.  **Preliminary offer:** Quick planning with satellite image only
2.  **On-site visit:** Measure roof, note dimensions
3.  **Final offer:** Adjust dimensions in Eturnity Expert for precise offer

**Advantages of precise planning:**

-   **Exact panel counts** – No surprises during installation
-   **Professional impression** – Shows the customer your diligence
-   **Easy readjustment** – Preliminary offer becomes final offer

## Video Tutorial: Roof Areas to Scale

In this video from our Video Training Center, you'll see both methods in action:

[Synthesia video player - EN - Draw the roof area to scale](https://share.synthesia.io/embeds/videos/13bdb45d-9fbc-410e-b4d7-74ed3ea842ef?language=en-GB)

## Method 1: Dimension Adjustment with Move Tool (Recommended)

This is the *fastest and most practical* method for the vast majority of cases. It's perfect if you've already created a preliminary offer based on the satellite image and now want to adjust the dimensions subsequently.

### Prerequisites

You already have:

-   A roof drawn in Pro Mode or Basic Mode (based on the satellite image)
-   The actual dimensions noted from the on-site visit

### Step-by-Step Instructions

**Step 1: Switch to drawing mode**

1.  Click on **"Roof Tool"** in the toolbar at the top
2.  Select the tool **"Select and Move"**
3.  *Alternative:* Hold down the `Shift` key to temporarily switch to the move tool

**Step 2: Select and move roof edge**

1.  Click on the roof edge you want to move
2.  The edge is highlighted and shows the current dimension
3.  **Hold down the mouse button** on the selected edge
4.  Drag the edge in the desired direction
5.  The displayed dimensions change in real-time

**Step 3: Use or disable snap mechanisms**

When moving, there are many snap points that help you quickly reach common dimensions:

-   **With snap points:** The edge automatically snaps at certain dimensions 
-   **Without snap points:** Hold down the `Ctrl` key (Windows) or `Cmd` key (Mac) to move freehand

> 💡 **Pro tip:** When moving freehand (with Ctrl key pressed), make sure the **yellow rectangles in the corners** are preserved. These indicate that the geometry is still intact and remains rectangular.

**Step 4: Optimize dimension precision**

Example: You want to reach exactly 6.00 m, but it shows 5.97 m or 6.03 m:

1.  Zoom in closer for finer control
2.  Hold down `Ctrl` for freehand moving
3.  Move the edge slowly until you're as close to 6.00 m as possible

> 💡 **Note on accuracy:** Small differences of a few centimeters (e.g., 34 mm) practically never make a difference in real planning for panel count or final result. Strive for "sufficient accuracy," not "perfect precision."

### Complex Shapes: Preserve Symmetry

A major advantage of the move tool: Even with more complex roof shapes, you can adjust dimensions *without destroying symmetry*.

**Example: Extend both eaves simultaneously**

1.  Select the **"Select and Move"** tool
2.  Select **both southern roof slopes** (with `Ctrl` + click for multiple selection)
3.  Hold down and move
4.  Both sides are adjusted simultaneously – symmetry is preserved!

**Why is this important?** With manual adjustment of each side individually, symmetry would easily be lost. The move tool automatically preserves geometric relationships.

### Inclination Remains Unaffected

An important point: Moving roof edges changes **only the length and width** of the roof areas, but *never* the inclination.

## Method 2: Precise Drawing with Calculator for Projected Lengths

This method is suitable when you want to draw the roof from scratch according to exact dimensions. It's somewhat more elaborate than Method 1, but offers maximum precision.

### Understanding the Concept: 3D Length vs. Projected 2D Length

This is the most important point for understanding this method:

-   **3D length (true length):** The actual length you measure on the sloped roof (e.g., 6.00 m)
-   **Projected 2D length:** The length when you view the roof from above – as in the floor plan (e.g., 4.92 m at 35° inclination)

**Why is this relevant?** When drawing in Eturnity Expert, you initially work in the 2D top view. So you need to convert the measured 3D length into the projected 2D length before you can draw it.

> 💡 **Visualization:** Imagine a sloped roof. Measured from the side, it's 6 m long. When you look at it from directly above (bird's eye view), it appears shorter – that's the projected length.

### The Calculator for Projected Lengths

Eturnity Expert offers a built-in calculator at the top of the toolbar:

**How to use the calculator:**

1.  Click on the **calculator symbol** at the top of the toolbar
2.  Enter the **true 3D length** you measured (e.g., 6000 mm)
3.  Enter the **roof inclination** (e.g., 35°)
4.  The calculator shows the **projected 2D length** (e.g., 4915 mm)
5.  You then use this 2D length when drawing

### Step-by-Step: Draw Roof to Scale

**Preparation:**

1.  Note all measured dimensions from the roof:
    -   Eave length (parallel to ridge)
    -   Roof slope length (from ridge to eave)
    -   Roof inclination in degrees
2.  Calculate the projected 2D lengths for all sloped edges with the calculator

**Drawing with direct dimension input:**

1.  Select the **Roof Tool**
2.  Start drawing at a corner
3.  **While drawing a line,** type the length in millimeters on the keyboard (e.g., `12500` for 12.5 m)
4.  A snap point appears at exactly this length
5.  Click to end the line at this snap point
6.  Repeat this for all sides

### Extrude Roof with Correct Inclination

After drawing the 2D floor plan, extrude the roof:

1.  Switch to the **Height Tool**
2.  Select the **ridge**
3.  Drag upward with the mouse button pressed to the desired inclination (e.g., 35°)
4.  The 3D length of the roof slope should now correspond to the measured length

**Fine-tuning the inclination:**

If the 3D length doesn't match exactly (e.g., 5965 mm instead of 6000 mm):

1.  Select the roof area
2.  Enter the **exact inclination** on the left (e.g., 35.00°)
3.  Confirm with Enter
4.  Repeat this for all roof areas with the same inclination

> 💡 **Note:** Small deviations occur because the display of roof inclination in degrees is rounded. Through exact input, the dimensions become accurate to the millimeter.

## Comparison: Which Method When?

| Criterion | Method 1: Move | Method 2: Calculator |
| --- | --- | --- |
| **Time required** | 1-2 minutes | 5-10 minutes |
| **Learning curve** | Very simple | Requires understanding |
| **Starting point** | Existing preliminary offer | Draw completely new |
| **Symmetry** | Automatically preserved | Manually ensure |
| **Best application** | Readjust after on-site visit | Complex special cases |
| **Recommendation** | ⭐⭐⭐⭐⭐ For 95% of cases | ⭐⭐⭐ Only when needed |

## Best Practices for Precise Planning

### During On-Site Roof Measurement

-   **Note all important dimensions:** Eaves, roof slopes, distances to dormers
-   **Photograph the roof:** Helps later for reconstruction
-   **Mark obstacles:** Roof windows, chimneys, vents with dimensions
-   **Check the inclination:** With inclinometer or app

### When Implementing in Eturnity Expert

-   **Start with the preliminary offer:** First draw roughly based on the satellite image
-   **Adjust afterward:** Use the move tool for quick adjustments
-   **Check symmetry:** Make sure the building remains symmetrical
-   **Compare panel counts:** Preliminary offer vs. final offer – large deviations indicate errors

## Common Mistakes and How to Avoid Them

### Mistake 1: Using 3D Length Instead of 2D Length

**Problem:** You enter the measured 3D length directly when drawing, without converting it.

**Consequence:** The roof slopes become too long and the geometry is incorrect.

**Solution:** Use the calculator for projected lengths to calculate the 2D length.

### Mistake 2: Destroying Symmetry When Adjusting

**Problem:** You adjust each side individually and don't pay attention to the overall geometry.

**Consequence:** The building becomes asymmetrical and looks unprofessional.

**Solution:** Use multiple selection with `Ctrl` + click to adjust opposite sides together.

## Summary

**The key takeaways:**

-   For **95% of cases**, Method 1 (move tool) is the best choice
-   The typical workflow: Preliminary offer (satellite image) → On-site measurement → Readjustment (move tool)
-   **Preserving symmetry** is more important than millimeter accuracy
-   Small deviations are usually completely uncritical in practice
-   The calculator for projected lengths is only needed if you're drawing completely new according to dimensions

**Expected result:** With these techniques, you can convert a preliminary offer into a dimensionally accurate final offer in 1-2 minutes that correctly represents the actual on-site conditions.

## Next Steps

After mastering precise drawing, we recommend:

-   **Placing Panels Flexibly: Techniques and Best Practices** – Optimize panel coverage on your precise roof areas
-   **Modeling Complex Roofs and Dormers** – When you also need to implement complex geometries to scale
-   **Pro Mode: Professional 3D Planning** – If you're still working in Basic Mode and want to switch to Pro Mode

The complete [**Video Training Center – Module 3**](https://eturnity.productfruits.help/de/article/modul-3) shows all techniques visually and with practical examples.