--- title: "Annotate Your Render with Mark up | Gendo" description: "Draw directly onto an image to tell Gendo exactly what to add and where." lang: en json-ld: --- [![Gendo](https://assets.gendo.ai/marketing/homepage/gendo-logo-white.png)](/) [Features](/product)[Solutions](/workflows)[Resources](/resources)[Pricing](/pricing) About [Log In](https://app.gendo.ai/sign-in)[Start creating ](https://app.gendo.ai/sign-up) [Back to Guides](/resources?tab=guides) Feature Guide 4 min read # Annotate Your Render with Mark up Draw directly onto an image to tell Gendo exactly what to add and where. Scroll to explore Contents 1. Introduction 2. Feature Overview 3. Workflow 4. Before and after 5. Tips 6. Related Links Introduction ## What is Mark up? Mark up lets you sketch straight onto your render and have Gendo turn those sketches into finished objects. It lives inside the **Edit** tool. Instead of describing a change in words alone, you draw where you want something to go, tag each drawing with a colour, then tell Gendo what each colour represents. It is the fastest way to add things that are not in the scene yet — the small touches you might otherwise take to Photoshop, such as a figure on the steps or a tree at the edge of the frame. Your drawing does not need to be neat. What matters is position and scale: a tree drawn tall renders tall, a figure drawn small renders small. Feature Overview ## Understanding the interface ### The Edit panel Click your image, then open **Edit** from the toolbar. The panel on the right holds everything you need. - **Area** — sets whether your change affects the **Whole image** or just a **Selected area**. - **Mark up** — a toggle to switch drawing on, a live count of how many marks are on the image, and two buttons, **Draw** and **Select**. - **Image reference (optional)** and **Description** — where you describe the change, followed by the **Generate** button. ![The Edit panel](https://assets.gendo.ai/marketing/learn/markup-panel-annotated.png) ### The drawing toolbar Once you start drawing, a toolbar appears beneath the image with brush options on the left and a colour palette on the right: red, white, orange, yellow, green, blue, pink, and black. Use a different colour for each kind of object so you can refer to them separately in your prompt. The panel also switches to show **Cancel** and **Save mark-up**. ![The drawing toolbar](https://assets.gendo.ai/marketing/learn/markup-drawing-toolbar.png) Workflow ## Step by Step 1 ### Open the Edit tool Click the image you want to work on, then select **Edit** from the toolbar. The Edit panel opens on the right. 2 ### Turn on Mark up In the **Mark up** section, switch the toggle on. You will see two options, **Draw** and **Select**. Choose **Draw** to add a new annotation. If the image already has marks on it, **Select** lets you pick an existing one instead. ![Turn on Mark up](https://assets.gendo.ai/marketing/learn/markup-panel-annotated.png) 3 ### Set your area Leave **Area** on **Whole image** to draw anywhere on the render. Switch to **Selected area** if you want both the drawing and the change confined to one part of the image. 4 ### Draw your marks and describe them by colour Pick a colour from the toolbar and draw where you want each object to go. Use a separate colour for each type of object, for example red for a figure and green for a tree. Keep the scale honest: draw the object at the size you want it to appear. **Note:** One continuous stroke, drawn without lifting your mouse or pen, counts as one mark. Check the number next to **Mark up** reflects what you have drawn. Only counted marks are sent to the generation, so a mark that is not registered will not appear in the result. Then open **Description** and tell Gendo what each colour stands for. Reference the colours directly so the model knows what each mark means. Example prompt: _the red mark is a person sitting and the green is a small tree_ ![Draw your marks and describe them by colour](https://assets.gendo.ai/marketing/learn/markup-marks-drawn.png) 5 ### Save and generate Click **Save mark-up** to lock in your drawing, then click **Generate**. Gendo produces two options. ![Save and generate](https://assets.gendo.ai/marketing/learn/markup-marks-drawn.png) 6 ### Choose a result and add it to the canvas Click a generation to preview it. When you find the one you want, double-click it or drag it to add it to the canvas. Your annotation is done. ![Choose a result and add it to the canvas](https://assets.gendo.ai/marketing/learn/markup-results.png) ## Before and after The prompt is: "The orange mark is an eagle, the green is a part of a tree visible next to a building and amber is a grass." ![The same render after generation, with an eagle, a tree and grass in place of the marks](https://assets.gendo.ai/marketing/learn/markup-compare-after.png)Generated ![Render with orange, green and amber mark up strokes drawn onto the façade view](https://assets.gendo.ai/marketing/learn/markup-compare-before.png)Marks drawn Drag the handle to compare before and after. Pro Tips ## Get Better Results Draw at the right scale, not the right detail — a rough shape at the correct size beats a neat shape at the wrong size. Use one colour per object type, then name each colour in your prompt so Gendo can tell your marks apart. Check the mark count before you generate. If a stroke did not register, it will not be included. Switch to Selected area when you only want to change one part of the scene and leave the rest untouched. Keep prompts simple and direct. A short line that maps colours to objects works better than a long description. Further Reading ## Related Links [Edit Your Render ](/resources/learn/edit-tool) [Swap Material ](/resources/learn/material-transfer) [Studio Interface ](/resources/learn/studio-interface) ## Related Tutorials [View all](/resources?tab=guides) [ ![Using the Edit Tool](https://assets.gendo.ai/marketing/learn/edit-tool-overview.png) Feature Guide ### Using the Edit Tool Make targeted changes to an existing image without regenerating the entire scene. ](/resources/learn/edit-tool) [ ![The New Canvas](https://assets.gendo.ai/marketing/homepage/gendo-ai-collaborative-canvas-interface.webp) Platform ### The New Canvas An introduction to Gendo's AI-powered architectural design canvas. ](/resources/learn/the-new-canvas) [ ![Studio Interface](https://assets.gendo.ai/marketing/studio-canvas-overview.png) Getting Started ### Studio Interface The main creative workspace — an infinite, in-browser canvas for managing images, renders, and notes. ](/resources/learn/studio-interface) [Gendo ](#) A living canvas for visual exploration, iteration, and decision-making. ### Product - [Product](/product) - [Pricing](/pricing) - [FAQs](/faqs) ### Company - [About Us](/about-us) - [Career](/career) - [Environmental Statement](/about/environmental-statement) - [Blog](/resources/insights) - [Contact Us](/book-call) ### Connect - [LinkedIn](https://linkedin.com/company/gendo-ai) - [Instagram](https://instagram.com/gendo.ai) - [YouTube](https://youtube.com/@Gendo-ai) © 2026 Gendo. 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