Frequently Asked Questions

Zoo Design Studio is a unified Hybrid CAD platform built on our proprietary geometry engine. It combines AI-driven generation and editing of boundary-representation CAD models with familiar sketch and feature tree workflows, brings code to CAD through KCL, and includes Zookeeper, our conversational CAD agent.

Zoo Design Studio is best used by downloading and installing our native desktop applications. There is a web browser test environment but it is meant to be used as more of a testing environment.

Visit our downloads page to install the desktop application.

Zoo Design Studio is available for free, and our free version includes 20 minutes of free Zookeeper reasoning time. We have paid tiers that include additional Zookeeper reasoning time. You can view our pricing here.

No. Zoo Design Studio is CAD software that anyone can use and download for free. There are paid subscription tiers that unlock more powerful features and capabilities, like unlimited Zookeeper credits and support for teams and enterprises. Visit our pricing page for more details.

Yes. Zoo Design Studio requires an internet connection because processing and our geometry engine run in the cloud. This lets you handle complex CAD workflows smoothly, even on low-powered machines.

Zoo Design Studio has solid modeling features like extrude, sweep, loft, revolve, shell, hole, booleans, etc. For a full list of features, visit our documentation.

Yes. Assemblies have been supported in Zoo Design Studio since v1.0. However, Assembly Mates are still on our roadmap.

We constantly ship updates to Zoo Design Studio. We do not currently follow a scheduled release cadence, which allows us to release exciting features and bug fixes as quickly as we can. To get a better idea of upcoming releases, check out Zoo's roadmap.

These are the current file types that are compatible with Zoo Design Studio:

• KCL
• STL
• glTF/GLB
• OBJ
• FBX
• PLY
• STEP/STP*
• SLDPRT* *experimental

You can export your project into the following file types:

• STEP
• STL
• glTF
• OBJ
• PLY
• FBX

Zookeeper is the AI CAD agent built into Zoo Design Studio. It can create and edit parametric CAD models from prompts, images, and sketches.

Click the sparkles icon in the right control bar. Zookeeper opens as a pane alongside your active project, where it can use your model, selections, renders, and KCL as context.

Visit the Zookeeper FAQs to learn more about its capabilities, workflows, and limitations.

KCL (KittyCAD Language) is Zoo's own scripting language for describing CAD geometries and rendering them within Zoo Design Studio. Every CAD function in Zoo Design Studio generates KCL. Using KCL in Zoo Design Studio is completely optional and is not required. KCL allows designers to leverage the benefits of code in the CAD ecosystem. Learn more by reading our KCL book.

No! Coding with KCL (Zoo's CAD coding language) is completely optional. However, it can be quite powerful. If your curiosity gets the best of you, you can learn more about getting started with KCL for coding in CAD on our Community Page.

Yes, the Zoo Design Studio application is open source and you can find it on GitHub. However, our CAD geometry engine is not open source.

Check out our developer documentation to get started designing your own modeling tools.

Anyone can ask questions, discuss workflows, and get help through our Community Forum or Discord. Paid customers who are signed in can also submit a private support ticket for issues that need direct assistance.

You can report bugs through our Community Forum or Discord. For Zoo Design Studio bugs, you can also open a GitHub issue. Please include reproduction steps, screenshots, logs, or example files when possible. Paid customers who need private assistance can also submit a support ticket while signed in.

If an update is needed, a notification will appear the next time you open Zoo Design Studio. Once the update is complete, you will need to restart your application for it to take effect. You can also click "Settings" in the bottom toolbar, click to the "About" section, and view your current version or check for updates.

You can use our Community Page to see if someone else has requested the same thing. If no one has, make a new request using the feature category.

Zookeeper is an AI agent for CAD built into Zoo Design Studio. It turns text prompts, images, and sketches into real, parametric CAD models.

Describe your goals and constraints, then delegate tasks such as creating geometry, validating designs, and analyzing manufacturability. Every model remains fully editable through familiar sketch and feature-tree workflows, with human-readable KCL as its source of truth.

Anyone from beginners and non-engineers to expert CAD users and enterprise teams can benefit from Zookeeper. It speeds up design by turning plain text requests into editable parametric KCL models for newcomers, while saving time for more experienced users with rapid prototyping, project-aware edits, and repeatable workflows that scale for teams.

Zookeeper is a pane on the right side. Click the sparkles icon in the right control bar to open it. It's context-aware and works with your active project to create or edit designs.

Zookeeper can generate a wide range of CAD models, from simple primitives and brackets to mechanical parts, enclosures, mounts, assemblies, and 3D-printable components, all from prompts or images. It can also edit existing models, interpret selected geometry and renders, and update the active project by producing or modifying parametric KCL code.

Yes - Describe what you want and Zookeeper will try to generate the geometry as parametric KCL. If generation fails or needs tweaking, it will suggest prompt refinements or follow-up edits.

Yes - Zookeeper analyzes your active project and offers context-aware suggestions (e.g., add fillets, mounting holes, or adjust dimensions) to help you decide the next modeling steps. It can also propose small edits or refinements you can apply immediately. It conducts relevant research, proposes design constraints and parameters, and generates a clear design plan before producing a CAD model.

Yes - Zookeeper understands and uses your selections in the active project. When you select faces, edges, bodies, or code regions, Zookeeper uses that context to make targeted edits, add features, or generate more precise prompts.

Yes - Zookeeper can view and interpret the project's renders and multiview snapshots to understand geometry and suggest or make context-aware edits. It uses those visual cues alongside selections and KCL to produce more accurate modifications. The team added engine-level tools that allow the agent to inspect, snapshot, and debug geometry while generating production-ready CAD.

Yes - You can ask Zookeeper questions about modeling, KCL, design decisions, or your active project. It can research using the internet, explain tradeoffs, and make manufacturing-aware suggestions. When you ask, Zookeeper can also perform edits, apply changes, or generate models directly in your design. The Enterprise version of Zookeeper can also be asked questions relevant to your design rules and internal company knowledge.

Yes - Zookeeper can compute surface area, volume, mass, and center of mass for the active project and return results in common units (e.g., mm³, m², kg). It uses the model geometry and material/density info from the project to make these calculations.

Be specific about what you want (dimensions, constraints, intended use) and include selections or reference geometry in the active project - clear prompts produce more accurate KCL results. Iterate: review the generated model, tweak parameters or ask for targeted edits, and accept Zookeeper's suggestions (fillets, holes, thickness changes) to quickly refine the design.

Zookeeper understands natural-language prompts (primarily English) and can read and work with KCL code and selected geometry in your project. It also accepts many major languages (Spanish, French, German, Chinese, etc.) with varying accuracy, though the best results are typically in English.

Auto Mode helps Zookeeper choose the right model for your prompt automatically.

If you're on the Free Plan, you won't need to pick between Standard and Thoughtful mode. Instead, Zookeeper will use Auto Mode to select the model that makes the most sense for what you're asking. Some prompts need deeper reasoning, while others can be answered just as well with a faster, lighter model.

This helps free users get more out of their included credits by avoiding unnecessary use of more expensive reasoning when it isn't needed. Fancy when it matters, efficient when it doesn't.

Users on paid plans can choose between Standard and Thoughtful mode themselves.

KCL (KittyCAD Language) is Zoo Design Studio's domain-specific, parametric CAD programming language. KCL projects are collections of .kcl files (entrypoint: main.kcl) that programmatically create 3D geometry using primitives, sketches, transforms, booleans, and parameters.

Zookeeper is our built-in CAD design assistant inside Zoo Design Studio that helps you work with KCL: it can generate new KCL models from plain-language prompts, edit your existing .kcl code, answer questions about KCL, and propose design changes, acting as an intelligent, context-aware partner while you design.

Yes - Zookeeper can read your KCL code, explain syntax and structure, and help fix or improve scripts. It can also suggest idiomatic KCL patterns and make project-aware edits when you ask.

Yes - Zookeeper can read and understand your KCL code, explain what it does, and use that context to suggest fixes or make targeted edits to the active project.

Yes - Zookeeper references official KCL materials (including the KCL Book) to ensure advice and code follow best practices. See the KCL Book for details.

Yes - Zookeeper can identify and fix KCL errors by analyzing your project and selected code, then applying targeted edits. If an automatic fix can't be applied, it will explain the issue and suggest a clear repair or simplified prompt for you to approve.

Yes - Zookeeper can explain mechanical design concepts, recommend best practices (tolerances, fastening, draft, fillets), and help apply them to your model. It can provide guidance and simple calculations, but it doesn't replace engineering validation or guarantee manufacturability or structural performance.

• Can: create/edit KCL CAD models, explain KCL/design concepts, and make changes via the studio's AI actions.

• Cannot: run physical tests, guarantee manufacturability or structural safety, or perform detailed engineering simulations.

• Interaction rules: modifies projects only through the studio's built-in code actions and cannot paste raw KCL or show rendered images in chat.

• Knowledge bounds: limited to its training and available docs; ask for clarification when requests are vague.

• Change ZDS application settings.

• Control the viewport (you must rotate, pan, zoom manually).

• Open or switch to other projects.

• Export models or files.

• Display backend-generated progress images.

• Read files outside the active project directory.

• Access your Zoo account or personal account information.

Zookeeper makes an initial attempt and, if it encounters errors, will examine the error messages and try up to five automated fixes. If those attempts still fail, it stops, reports the problem, and offers simpler prompts or clarification options for you to choose.

If a Zookeeper prompt fails, it stops and shows the error(s), explains what went wrong, and offers next steps - like a simpler prompt, clarification questions, or manual edits. It may try up to five automated fixes for edit actions; if those still fail it won't retry automatically and will wait for your instruction to proceed.

Yes. Zookeeper can make mistakes - it may misunderstand intent, produce incorrect geometry, or suggest designs that aren't manufacturable or safe. Always review and validate changes, run your own checks, and give clear, specific instructions or corrections when needed.

Short answer: Not persistently. You can give explicit instructions, constraints, or coding style rules in each prompt (and selections/params in the project guide edits), and Zookeeper will follow them for that action. It doesn't support global, always-on custom agent rules or persistent personality settings across sessions.

Break the task into smaller steps. Ask Zookeeper for a design plan first, then request geometry changes one feature at a time. Example flow:

1. "Create the rectangular base."

2. "Add corner holes."

3. "Fillet the edges."

Working incrementally (and giving clear dimensions or constraints) gets better results than one large, vague prompt.

Select the exact geometry and give a concise instruction.

• In the UI, highlight the face/edge/body or select the relevant lines in the code before asking.

• Use clear, specific commands (e.g., "change this hole diameter to 5 mm" or "fillet these two edges with 2 mm").

• Reference named parts or parameters if available (e.g., "modify mount_plate.thickness").

• Provide constraints or intent when helpful (fit a M4 screw, keep wall ≥2 mm).

Doing this ensures Zookeeper applies changes to the correct part rather than guessing.

You can report bugs in several ways.

1. Submit a GitHub issue

2. Report bugs on our Discord server

3. Ask our team via our Community Forum

Yes! Zookeeper is built on the Agent API, and will call any Zoo tool necessary to get the job done. It supports uploading images, documents, 3D models and text as sources to work from.

Zookeeper usage is included with Zoo Design Studio plans as monthly reasoning time.

• Free plans include 20 minutes per month

• Plus plans include ~400 minutes per month

• Pro plans include unlimited reasoning time

If you use up the reasoning time included in your plan, usage pauses by default. You can enable pay-as-you-go at $0.0083 per second or upgrade to a higher plan.

Enterprise plans are tailored to each organization, including its team size, deployment needs, support requirements, and workflows. Contact our team to discuss custom or volume pricing.

Yes. Zoo can work with your CAD files, engineering documents, specifications, and design standards to support organization-specific modeling and automation workflows. Contact our team to discuss your requirements and whether an Enterprise pilot is a good fit.

You'll need a representative subset of native CAD files with full feature trees plus associated engineering documentation and guidelines. Neutral formats like STEP and IGES typically lose parametric intelligence and are not ideal for model customization. We can explore a Team Pilot with additional support if your company is lacking access to 3D CAD data.

Plan for up to 100 representative models from a focused part family to start; broader coverage usually improves robustness. Include associated design standards, product requirements, and manufacturing guidelines to align outputs with your internal rules.

A typical pilot follows a clear sequence: jointly select a target part family and success metrics; provide representative native CAD files, standards, and documentation; let Zoo fine-tune your private model; evaluate it against reference designs and internal rules; then expand to additional families and workflows. Success is measured by editability, guideline compliance, accuracy against reference parts, and time saved per iteration.

Yes. Zoo can fine-tune a private model on your organization's CAD data and engineering knowledge so its output better reflects your part families, standards, and workflows. Contact our team to discuss your use case.

Zoo works especially well today with SolidWorks (.sldprt) and Creo (.prt) native files whose feature trees remain intact. CATIA (.catpart) support is actively in progress. Zoo can also ingest formats from ecosystems such as NX (.prt) and Autodesk Fusion (.f3d), depending on the workflow, but authoring-native data that preserves parametric intent and history produces the best fine-tuning results.

Zoo works best today with solid-modeled parts and well-defined mechanical part families. Surface-heavy use cases are at an earlier stage, with broader support expected to grow throughout 2027. Zoo supports assemblies, but does not yet support mating or a full assembly constraint solver.

Production-ready 2D drawings, mates for assemblies, and STEP to KCL are also on the roadmap.

Your data remains your IP. By default, Enterprise training is isolated in a single-tenant setup, and private model weights are not shared with other customers. Zoo only needs the rights required to process your data and train the private model delivered to your team.

Independent auditors have verified Zoo's security controls through a SOC 2 Type II audit. Zoo's US Regulated region is suitable for processing or storing export-restricted (ITAR) information and runs on US-based cloud infrastructure that meets ITAR baselines. Customer-controlled deployment options include private cloud, government cloud, and on-premises environments. See the Zoo Trust Center for the current report and security details.

Zoo's Engine API, Agent API, and File Format API can create and edit geometry, run AI-assisted CAD workflows, and convert files within your own applications and internal systems. Zoo MCP connects Zoo-backed CAD tools to Claude, Codex, and other MCP-compatible AI clients. For PLM, custom, or organization-specific integrations, contact our team to discuss your workflow.

The Free plan gives you full access to Zoo Design Studio, including all core CAD workflows. Zookeeper is included with 20 minutes of reasoning time per month, and Zoo may train on data from Free plan usage to improve our products.

We'll notify you when you're close to or have used up your included reasoning time. You can upgrade at any time from your account settings. If you run out of included reasoning time, usage pauses by default. You can enable pay-as-you-go at $0.0083 per second or upgrade to a higher plan with more included reasoning time.

Included monthly credits refresh on the first day of each calendar month (UTC), regardless of when you signed up or when your monthly or annual subscription renews. New accounts receive the credits included with their current plan when the account is created.

The refresh replaces your remaining monthly credit balance with the full monthly amount included in your current plan, so unused monthly credits do not roll over or accumulate. Changing plans can also update your included monthly credit balance.

Promotional or other credits granted separately by Zoo are not monthly credits: they are not replaced during the monthly refresh. Usage draws from monthly credits first, then from separately granted credits. You can see your combined remaining credit balance on your Billing page.

After all available credits are used, usage pauses by default. You can continue on a pay-as-you-go basis if you enable it and have a valid payment method, or upgrade to a plan with more included usage. Otherwise, usage remains paused until the next monthly refresh.

Pay-as-you-go lets you continue using billable Zoo services after you have used all credits included with your Free or paid plan, as well as any separately granted credits. Additional usage is charged at the applicable pay-as-you-go rate.

The setting is off by default. While off, usage pauses after your available credits are exhausted, so you will not incur overage charges. You can turn pay-as-you-go on or off from your Billing page. A valid payment method is required before pay-as-you-go charges can be incurred.

Zoo now requires explicit consent before usage can continue beyond your available credits and generate overage charges. Previously, eligible accounts could continue on a pay-as-you-go basis without enabling a separate setting.

Requiring an explicit opt-in gives you direct control over whether your usage should stop at your plan's limit or continue as paid overage usage. You can review or change your choice at any time from your Billing page.

Turning pay-as-you-go off does not affect the credits already included with your plan. You can continue using Zoo until all available included and separately granted credits have been used.

After those credits are exhausted, billable usage pauses instead of generating additional charges. Usage can resume when your monthly credits refresh, when you receive additional credits, when you upgrade to a plan with more included usage, or when you turn pay-as-you-go back on. Turning it off does not reverse charges for usage that has already occurred.

The Pro plan includes unlimited Zookeeper reasoning time inside Zoo Design Studio. API usage outside Zoo Design Studio is separate: it uses your included API credits first, then continues at pay-as-you-go rates only if you have enabled pay-as-you-go and have a valid payment method.

We do! You can pay month-to-month and contact us to cancel any time. If you opt for an annual plan, you get a 20% discount in exchange for paying upfront and remaining committed to that plan for an entire year.

We accept credit cards for all paid plans. For Team or Enterprise plans, if you need custom billing, please contact us.

Yes, you can always upgrade or downgrade your plan to another tier without losing your data.

Visit our Getting Started documentation and YouTube channel for the latest onboarding resources.

On the Free Plan, Zookeeper reasoning time is capped at 20 minutes per calendar month. If you use all of your included time, you can continue on a pay-as-you-go basis if it is enabled and you have a payment method, upgrade to Plus for more included reasoning time, or wait for your credits to refresh on the first day of the next calendar month (UTC). Pro, Team, and Enterprise plans include unlimited Zookeeper reasoning time in Zoo Design Studio.

Visit the Zoo Enterprise FAQs for information about custom pricing, pilots, model customization, security, deployment, and integrations.

API calls are charged by the second. Each second costs ~$0.0083.

Rounding: We compute elapsed_seconds x $1/120, then round Half-Up to the nearest cent per call. We never round the time itself.

Short calls policy: Historically, sub-10-second calls were not billed. Since October 14, 2025, they have been billed per second with the same rate and rounding.

Note: because we round each call to cents, many tiny calls can sum to a hair more than one long call with the same total seconds. This is standard for usage billing. If that ever meaningfully impacts you, tell us.

For more information on how the math works, see Jess's blog post here.

All users get $10.00 worth of API calls per month for free. After those credits are used, API usage pauses unless pay-as-you-go is enabled and the account has a valid payment method.

Yes, all of our charged API calls are charged by the second. Each second costs ~$0.0083. For more information on how the math works, see Jess's blog post here.

No, you are not charged if the API call fails.

Generally no. GET requests are free, except for WebSocket-style GETs used for real-time features: endpoints that start with /ws/modeling/commands or contain /ws/ml/copilot are billable.

In general, any POST endpoint is billable unless it is on our exclusion list below. The only GET endpoints that are billable are WebSocket-style GETs for real-time features: endpoints that start with /ws/modeling/commands or contain /ws/ml/copilot.

Based on our current API specification (spec.json), representative billable POST endpoints include:

• /ai/text-to-cad/{output_format}

• /ml/kcl/completions

• /ml/text-to-cad/iteration

• /ml/text-to-cad/multi-file/iteration

• /ml/convert/proprietary-to-kcl

• /file/conversion

• /file/conversion/{src_format}/{output_format}

• /file/mass

• /file/volume

• /file/surface-area

• /file/density

• /file/center-of-mass

This list is not exhaustive; new billable endpoints may be added in the future. Always refer to the API spec and this FAQ for the latest billing behavior.

No. Endpoints that start with /user or /org are free and not billed.

No. Endpoints that start with /oauth2 are free and not billed.

The following endpoints are free and never billed:

• /_meta
• /user
• /logout
• /apps
• /events
• /org
• /store
• /_internal
• /auth
• /oauth2
• /debug
• Any endpoint containing shortlinks
• /file/execute/
• /ws/ml/reasoning/{id}

Agent API requests do not have a fixed completion time. Duration depends on the complexity of the task, the tools required, and the number of iterations the agent performs. Integrations should not assume a specific completion window.

Yes. We are working on our machine learning endpoints every day, but it is still experimental. Some results may not be as good as you expect.

The Agent API streams conversational responses and tool results. For CAD-generation tasks, those results can include editable KCL project files. Producing formats such as STEP requires a separate modeling and export step.

For assistance with APIs, you can ask a question on our Community Page or discuss on our Discord!

For bugs, mention it to us on our Community Page.

Please email us directly. We would love to chat with your specific needs and see how we can best help you.