Onshape Review: Browser CAD, Parasolid and Its Limits

Introduction: The Program Without a Save Button

9 March 2015. Cambridge, Massachusetts.

Onshape opened its public beta that day. Before the launch, the company had run pre-production testing with more than a thousand CAD professionals across 52 countries ^[10]. An iPhone app shipped alongside the browser client. There was no installer. No license key. No service pack. And strangest of all, there was no Save button anywhere on the screen.

For three decades, CAD software has negotiated a deal between the engineer’s disk and the program’s memory. You open a file. You lock it. You change it. You save it. If something goes wrong, you go back. Onshape cancelled that deal. Every edit landed in a server-side document as the user typed. When the laptop closed, no unsaved work remained.

Onshape is a browser-based, fileless SaaS (software as a service) computer-aided design platform. It computes geometry on cloud servers, keeps design data inside a single document, and renders the result to the user through WebGL ^[1][2]. It is developed by PTC, which acquired the company in 2019 in a deal valued at roughly $470 million ^[8].

The question behind this review is simple: does removing the Save button actually produce a better engineering tool? The answer depends on how much the user cares about where the design data lives and who can see it.

Onshape at a Glance

First Turn: The Kernel Is Not Theirs

The Onshape story is usually told as a cloud story. The more interesting part sits underneath the geometry.

Onshape did not write a geometry kernel. It licensed Siemens Parasolid. That fact rarely appears in marketing copy, yet Siemens lists Onshape explicitly among both its cloud adopters and its CAD licensees ^[7]. Parasolid is a B-Rep modeler with more than 900 functions, licensed by over 200 independent software vendors ^[7]. The same kernel also runs inside SOLIDWORKS, Solid Edge and Shapr3D.

This does not diminish Onshape. It clarifies what is genuinely new. The novelty is not solid-modeling mathematics; it is the data model. An independent industry analysis put it plainly in 2019: “The CAD technology in Onshape is good in itself, but not the most remarkable on the market. Instead what makes Onshape unique is how the solution is distributed, how it helps teams collaborate, and that it is both affordable and easy to start working with” ^[9].

In other words, the product’s claim is not “a better modeler”. It is “an infrastructure that removes the human traffic around a model”. Judging Onshape without understanding that is like reviewing a building’s facade while ignoring its foundation.

Second Layer: A Branch Is a Pointer, Not a Copy

In file-based CAD, separating an experiment means copying a file. The copy multiplies, names drift, and nobody is sure which revision is current. Onshape works in workspaces; opening a new branch does not produce a second file.

Onshape’s own documentation is direct about this: a branch is “not another file or a copy to maintain” but “a pointer to the original CAD model version where the branch originated” ^[4]. The default workspace is called Main. Every other branch derives from it and can be merged back. Merging can be selective at the solid or surface level, so a team can take the useful part of a branch rather than the whole thing ^[4].

The practical consequence is that two body designs for the same assembly can run in parallel inside one document, be compared, and then resolved. Onshape’s comparison tool shows the difference between two moments, two versions or two branches as a visual overlay plus a feature list ^[4]. When geometry conflicts, the system flags them before the merge and highlights the affected features; after a merge, the document history allows a rollback ^[4].

The classic PDM checkpoint does not exist here. That is not chaos by design. Every action is written into document history, which produces visibility rather than secrecy. But one warning is necessary: “no lock” does not mean “no responsibility”. Merging the wrong branch into Main is technically easy, so release discipline still rests on people.

Third Layer: FeatureScript Means Writing a New Button

The most technical and least understood part of Onshape is FeatureScript, a programming language in which users can author custom parametric features that run inside Onshape itself ^[5].

The distinction is best stated in one sentence: macros press existing buttons; API scripts drive the program from outside; FeatureScript defines a new button. Onshape’s own toolbar commands, including Extrude and Helix, are defined as functions in the Standard Library written in this language ^[6]. A custom feature is therefore not an add-on sitting outside the modeling environment. It becomes part of it.

The critical piece of that architecture is the query. A traditional macro says “take edge number 12” and breaks when the model changes. A FeatureScript query expresses intent: “find the edges produced by this operation”. When the model regenerates, the query runs again; a hole added upstream produces new edges, and the feature includes them ^[6]. Onshape calls this query replay: the rule is re-evaluated instead of a fixed identifier being remembered.

The result is a single, named row in the feature tree. A feature labeled “Bearing Seat” carries more design intent than a stack of offset, revolve-cut, groove, two chamfers and a fillet. Its parameters stay editable; it can be suppressed, reordered and driven by configurations ^[6].

The language is open-source and strongly typed ^[5][10]. It is written, tested and published inside Feature Studio, and published features can be shared with the community through the FeatureScript Library ^[5]. In 2026, Onshape Labs connected the language to AI agents through an MCP server, making natural-language authoring of custom features possible ^[5][6].

Honesty still applies: a production-grade custom feature demands programming knowledge and parametric modeling judgment. AI lowers the barrier; it does not remove it. Code maintenance, versioning and internal distribution remain engineering work.

Second Turn: The Free Plan Charges You in Visibility

Onshape’s free tier looks generous: unlimited public storage, CAD tools, real-time collaboration, version control, mobile apps and online training ^[1]. The price is zero dollars.

Then comes the rest of the sentence: the plan is for non-commercial use only, and all Onshape documents are accessible to the public ^[1]. The $0 label therefore means you have traded away the confidentiality of your design. For a hobby project, a student exercise or an open-source mechanism, that may be a fair exchange. For a client deliverable, a mechanism awaiting a patent filing or an assembly that carries competitive advantage, it is not.

There is a subtle point here. “Public” does not merely mean viewable by anyone with a link; those documents sit inside a catalog other users can browse. A team protecting a commercial idea should start on a paid plan from day one, not after the first customer meeting.

Third Turn: It Is Cloud, but Not Everything Is in the Cloud

Onshape’s hardware promise is real: modeling computation happens on the server, so a heavy workstation is not mandatory ^[2]. But “no hardware needed” is too broad a sentence.

Rendering happens on your machine, inside the browser’s WebGL context. Onshape’s hardware documentation says so directly: large assemblies benefit clearly from a discrete GPU, and less than 1 GB of video memory can cause the WebGL context to be lost and the model to fail to load ^[2]. The company’s 2024 hardware guide recommends at least 1 GB of VRAM for everyday work and 2 GB or more for large assemblies, with 8 GB of RAM as a baseline and 16 GB or more for power users ^[3].

The same guide offers concrete document-structure thresholds: 250 or fewer features per Part Studio, and 40 or fewer tabs per document ^[3]. These are guidance, not hard limits, but they describe the scaling model: a document receives server resources, and those resources do not grow automatically as data is added ^[3].

The second constraint is connectivity. Onshape does not work offline. When the connection drops, work stops; data is not lost, but production is ^[2]. The company notes that bandwidth demand is modest and that a connection able to carry a single video stream can support a team ^[2]. That is good news for a home office; it is harder to promise on a factory floor with an unstable network.

The third constraint is data residency and compliance. Onshape Government is positioned for ITAR/EAR support on AWS GovCloud and offers a FedRAMP Moderate environment ^[11]. Access to that edition is limited to authorized U.S. persons employed by PTC ^[11]. The bridge between “cloud CAD” and “sensitive defense data” is therefore not universal. An organization with its own residency rules should settle the question in writing before purchase.

2026 Pricing: What You Pay, and What You Do Not Get

The table below reflects Onshape’s official pricing page on 7 November 2026 ^[1]. Prices are billed annually and quoted per user.

The most important line in that table is usually skipped: the $1,000 gap between Standard and Professional is not just “more features”. It is company ownership of data and a release workflow. A professional team’s first real need is rarely raw modeling speed; it is the ability to show who approved which revision. That need starts at Professional.

There are also education, startup and discovery programs: students and educators can use professional-grade CAD at no charge; qualified startups can receive free licenses; and the Professional plan can be tried free for up to six months through the Discovery Program ^[1]. These should be counted in a purchase decision, but not treated as a permanent cost plan.

Who It Fits, and Who It Does Not

A good fit: distributed teams; manufacturers that must work on the same model with suppliers; hardware startups iterating quickly; student teams, robotics clubs and institutions that refuse to install anything outside a browser. Onshape’s real-time multi-user editing lets two engineers work on the same assembly simultaneously, which feels strange to teams raised on file locking and then becomes hard to give up ^[1][4].

A poor fit: teams working in field conditions without internet; organizations required to keep design data on their own servers; public bodies that can only buy perpetual licenses; and anyone planning to use the free plan for commercial work. For that last group the answer is unambiguous: the plan was not designed for it ^[1].

Scale deserves its own note. Onshape handles large assemblies well, but the document must be structured for it: sub-assemblies, version references, mates with fewer degrees of freedom and fewer unnecessary limits ^[3]. That is not a promise that a huge assembly will fly the moment it opens; it is a promise that a correctly built one will.

A Short Comparison With Alternatives

The decision sentence is this: choosing Onshape means choosing the least-friction collaboration infrastructure, not the most powerful modeler. If modeling depth is your yardstick, SOLIDWORKS or Creo still go deeper. If team coordination and data discipline are the yardstick, Onshape moves ahead.

Closing: No Save Button, No Fear of Losing Work

Onshape’s most radical act was removing a button. The Save button disappeared, and a document history that records every action took its place. But the same move introduced a new dependency: your design no longer sits on your disk. It sits behind a browser tab.

So the right question is not “is Onshape good?” The right question is “is this trade right for my work?”

One-sentence answer: Onshape is strong for teams that want design data to stop being a file and start being a shared team resource; it is the wrong starting point for anyone who puts the physical location and confidentiality of data above everything else.

A concrete step for today: spend a week with the free plan on a real assembly, but decide on day one whether the document must stay private. On the free tier, the currency you pay is not money. It is visibility.

Two questions: would your team genuinely gain from editing the same assembly at the same time? And if that assembly appeared in a public catalog, would your business suffer?

Sources

1. Onshape, “Plans and Pricing” — accessed 7 November 2026. https://www.onshape.com/en/pricing
2. Onshape Help, “Hardware and Graphics Performance Recommendations” — last updated 30 October 2026. cad.onshape.com/help
3. Onshape Blog, “Boost Your CAD Performance: Understanding Onshape Hardware Requirements” — 18 July 2024. onshape.com/en/blog
4. Onshape, “Branching & Merging in CAD” — product page, accessed 7 November 2026. onshape.com/en/features/branch-merge-cad
5. Onshape, “CAD Customization with Onshape FeatureScript” — product page, accessed 7 November 2026. onshape.com/en/features/custom-features
6. Darren Henry, “What Is FeatureScript? How It Differs from CAD Macros and APIs”, Onshape Blog — 27 August 2026. onshape.com/en/blog
7. Siemens, “Parasolid 3D Geometric Modeling” — product page, accessed 7 November 2026. siemens.com
8. PTC, “PTC to Acquire Leading SaaS Product Development Platform Provider Onshape” — 23 October 2019. ptc.com
9. Verdi Ogewell, “PTC’s Onshape Acquisition: Did SOLIDWORKS Founder Jon Hirschtick Have to Sell?”, engineering.com — 31 October 2019. engineering.com (archive)
10. Wikipedia, “Onshape” — accessed 7 November 2026; secondary source for founding, beta, FeatureScript and file formats. en.wikipedia.org/wiki/Onshape
11. Onshape, “Onshape Government” — product page and FAQ, accessed 7 November 2026. onshape.com/en/features/onshape-government
12. Onshape Help, “Supported File Formats” — last updated 30 October 2026. cad.onshape.com/help