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Using 3D-Agent

Prompting guidelines

Brief 3D-Agent the way you’d brief a 3D artist. The best prompts plan first, build in pieces and describe the result you want.

Plan first

For big or unclear tasks, get a plan before anything is built:

  1. Turn on Plan mode, or say Write a plan first. Don’t build anything yet. Nothing changes until you approve.

    The composer with Plan mode on: the Plan pill is highlighted and the composer has an orange dashed frameThe composer with Plan mode on: the Plan pill is highlighted and the composer has an orange dashed frame

  2. Ask for phases and steps, why each step matters, and what “done” looks like.

  3. Pin down anything vague, especially sizes, proportions and angles. Otherwise the agent has to guess. 3D-Agent can also ask you questions before it writes the plan. Pick an answer or click Skip.

    3D-Agent's questions before planning: what the avatar is for, whether the 6-stud height includes the horns, and how strict the closed-mesh check should be, each with a recommended answer3D-Agent's questions before planning: what the avatar is for, whether the 6-stud height includes the horns, and how strict the closed-mesh check should be, each with a recommended answer

  4. Say Implement, or Build it phase by phase, and check each phase.

I want to model a medieval knight for a game. Before building anything, write a detailed plan: split the work into phases, with steps and substeps, why each one matters, and how we’ll know each phase is done. Don’t build yet.

A plan from the agent, with Copy, New chat and Implement buttons under itA plan from the agent, with Copy, New chat and Implement buttons under it

Build in pieces

Follow-ups build on what’s already in the scene. Start with the main shape, then add detail one change at a time:

  1. Create a medieval Gothic church for a fantasy RPG.
  2. Add a bell tower on the left and make the windows taller.
  3. Add stone materials and moss on the lower walls.

A short follow-up can change the whole scene. Here, Create a small Minecraft-style floating island with a house, trees and a waterfall was followed by Make it winter:

A blocky floating island with a timber house with a red roof, three cube trees, a fence, a stream and a waterfall pouring off the edgeA blocky floating island with a timber house with a red roof, three cube trees, a fence, a stream and a waterfall pouring off the edge
The same island in winter: snow on the ground, roof and trees, a frozen stream and waterfall, and warm light in the windowsThe same island in winter: snow on the ground, roof and trees, a frozen stream and waterfall, and warm light in the windows

For complex models, build each part on its own, like the helmet, armor and sword, then ask to group them. Each prompt saves a checkpoint.

Many heavy operations in one prompt can freeze Blender, especially on slower computers. Split big jobs into several prompts.

Describe the result, not the steps

Give the details an artist would ask for:

  • What: the object or change
  • Style: realistic, stylized, low-poly
  • Size and placement: “about 2 m tall, next to the desk”
  • Count and naming: “four chairs named Chair_01 to Chair_04”
  • Purpose: “for a Unity mobile game”, “for a close-up render”
  • Measurements: “a 1.2 m wide window”, “20 × 15 units”. For real buildings or products, give real dimensions or attach a drawing.
Instead ofTry
Make a houseBuild a modern two-story house with a glass facade and a rooftop garden, about 10 m wide, centered at the origin
Fix the lightingMake the lighting warm and soft, like late afternoon, and remove the harsh shadow on the sofa

One precise sentence can be enough when it names the parts, the material and the pose:

A desk lamp with an articulated two-joint arm and a round metal shade, in a bent working pose.

A desk lamp with a teal round shade and base, two aluminum arm sections with springs, brass-accented pivots and a power cable, on a studio backgroundA desk lamp with a teal round shade and base, two aluminum arm sections with springs, brass-accented pivots and a power cable, on a studio background

Let the agent work

3D-Agent inspects the scene, takes screenshots, checks the result and fixes what’s off. That loop is what makes it reliable.

Say what “right” looks like, and the agent checks it before it finishes:

Create a floor slab 4.6 × 4.8 × 0.1 m, four exterior walls 2.7 m high and an interior wall at x = 2.2 m. Check: no gaps at the corners.

A white floor slab with four exterior walls and one interior wall dividing it in two, seen from aboveA white floor slab with four exterior walls and one interior wall dividing it in two, seen from above

Give it references

  • Type @ to mention an object, or select objects in Blender and say the selected objects.

    The @ menu under the composer, listing scene objects grouped as Cameras, Lights and MeshesThe @ menu under the composer, listing scene objects grouped as Cameras, Lights and Meshes

  • Attach a reference image and describe it in words too. Images, text and measurements together work best. Here, a picture of a mushroom character went in with Build this character as a Roblox avatar.

    The reference picture: a cute mushroom character with a coral cap with cream spots, a smiling face and rosy cheeks, on a mint backgroundThe reference picture: a cute mushroom character with a coral cap with cream spots, a smiling face and rosy cheeks, on a mint background
    The result: the mushroom rebuilt as a blocky Roblox-style avatar, with the spotted coral cap and smiling face on a body of rounded cream blocksThe result: the mushroom rebuilt as a blocky Roblox-style avatar, with the spotted coral cap and smiling face on a body of rounded cream blocks

  • Send one view per image. A sheet with many views confuses the agent.

  • For real objects, ask for research first: Look up the real dimensions of a Vespa scooter, then plan the model.

  • Attach a PDF or document, or add it to a project so every chat can use it.

For a consistent style, add a short .md file to a project with the colors, level of detail, polygon budget and naming. Every chat in the project reads it.

A project page with its composer, the Conversation list of its chats and the Files card with three reference filesA project page with its composer, the Conversation list of its chats and the Files card with three reference files

Set rules and limits

Say what to avoid, not only what to make:

  • Don’t change my viewport settings or bone colors.
  • Don’t use the Shrinkwrap modifier.
  • Keep it under 10,000 triangles, and use only boxes and cylinders.

With limits like these, a low-poly cafe came out engine-ready at 6,648 triangles. The full prompt is in Example prompts.

A low-poly cafe seen from above with no roof: a kitchen along the back wall, an order desk at the front, round tables with orange chairs and wide walkways, in flat teal, cream and orangeA low-poly cafe seen from above with no roof: a kitchen along the back wall, an order desk at the front, round tables with orange chairs and wide walkways, in flat teal, cream and orange

If a task could go more than one way, say which you want, or the agent picks: Prefer adding edge loops over smoothing the whole mesh.

If parts float apart or overlap, ask the agent to compare their positions, taking parent and child objects into account: Compare the placement of the floors and the railings using local and world coordinates, then fix the gaps.

Keep chats focused

Use one chat per task or asset. Every turn carries the chat’s history and screenshots, so long chats get slow. See Long chats.

If the agent goes in circles, start a new chat and describe what you learned in the first one.

Write prompts in English for the most reliable results.

Next steps

Example prompts

Copy real workflows from 3D-Agent users.

Model a game prop

Go from a description to an exported asset.

Chat and composer

Attach images, mention objects and use Plan mode.

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Make a motion referenceExample prompts