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CAD · head to head

MoI (Moment of Inspiration) vs SolveSpace

MoI (Moment of Inspiration) logo

MoI (Moment of Inspiration)

CAD

NURBS modeller bought once, built for designers rather than engineers

From
On request
Rated
-
Full reviewWebsite
S

SolveSpace

CAD

Open source parametric CAD with a constraint solver in a few megabytes

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only SolveSpace has a free tier, so it costs nothing to try first.
  • Each has a real cost: MoI (Moment of Inspiration) it is developed by one person, so releases are years apart and there is no support organisation to escalate to when something blocks your work.; SolveSpace the in-house geometry kernel fails on complex boolean operations and fillets, and the failure is sometimes silent bad geometry rather than an error message, so models must be checked before export or manufacture.
  • They diverge on capability: MoI (Moment of Inspiration) covers Direct NURBS modelling, SolveSpace covers Constraint solver.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which MoI (Moment of Inspiration) and SolveSpace actually diverge.

Attributes where MoI (Moment of Inspiration) and SolveSpace differ
AttributeMoI (Moment of Inspiration)SolveSpace
Starting priceOn requestFree
Pricing modelOne-time purchaseOpen source, no licence fee
Free tierNoYes
PlatformsWindows, macOSWindows, macOS, Linux

Identical on both: user rating (Not yet rated), category (CAD).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in MoI (Moment of Inspiration)

  • Direct NURBS modelling
  • Clean mesh export
  • Pen-oriented interface
  • Boolean toolset
  • STEP and IGES exchange
  • Scriptable commands

Only in SolveSpace

  • Constraint solver
  • Solid modelling
  • Assemblies
  • Export formats
  • Cross-platform
  • Small footprint

What people use each for

The jobs each tool is most often brought in to do.

MoI (Moment of Inspiration)

  • Converting CAD surfaces into clean quad meshes for a polygon or sculpting applicationnot SolveSpace
  • Modelling hard-surface concept designs where form matters and engineering documentation does notnot SolveSpace
  • Working on older or low-specification hardware that will not run mainstream CADnot SolveSpace
  • Buying a modelling tool outright rather than committing to a recurring CAD subscriptionnot SolveSpace

SolveSpace

  • Designing 3D printed parts on a machine that cannot run mainstream CADnot MoI (Moment of Inspiration)
  • Teaching constraint-based parametric modelling without buying licences for a classroomnot MoI (Moment of Inspiration)
  • Checking that a mechanical linkage moves as intended before cutting metalnot MoI (Moment of Inspiration)
  • Producing dimensionally accurate STEP or STL output from a small open source toolchainnot MoI (Moment of Inspiration)

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

MoI (Moment of Inspiration)

  • It is developed by one person, so releases are years apart and there is no support organisation to escalate to when something blocks your work.
  • There is no parametric history and no assembly structure, so a late design change means remodelling rather than editing a feature.
  • It produces no dimensioned drawings or manufacturing documentation, so anything heading for production needs a second package for the paperwork.
  • Exchange is limited to surface formats such as STEP and IGES with no native interoperability with mainstream MCAD systems, so it sits at the edge of an engineering pipeline rather than inside it.
  • Each major version is a fresh purchase, and the long gaps between versions mean a fix or a feature you need can be several years away with no interim release.

SolveSpace

  • The in-house geometry kernel fails on complex boolean operations and fillets, and the failure is sometimes silent bad geometry rather than an error message, so models must be checked before export or manufacture.
  • There is no proper drawing and dimensioning workflow, so manufacturing documentation has to be produced in another application.
  • Development is volunteer-led and intermittent; long gaps between releases are normal and there is no support contract available at any price.
  • Assembly-level import of external CAD is very limited, so it does not fit a supply chain that exchanges native or assembly-level models with suppliers.
  • The interface follows its own conventions rather than mainstream CAD ones, so existing SolidWorks or Fusion users spend time unlearning habits for a tool with a lower ceiling.

Pricing, plan by plan

MoI (Moment of Inspiration)

On request
  • MoI$undefined/year
    • Perpetual licence for one major version
    • Windows and macOS
    • Paid upgrade for each subsequent major version

SolveSpace

Free
  • SolveSpaceFree
    • Full application under the GPL
    • No seat limit
    • Windows, macOS and Linux builds

Which should you pick?

Choose MoI (Moment of Inspiration) if

  • You need direct nurbs modelling.
  • You work on Windows, macOS.
  • You also want clean mesh export.
MoI (Moment of Inspiration) review

Choose SolveSpace if

  • You need constraint solver.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want solid modelling.
SolveSpace review

Questions people ask

Is MoI (Moment of Inspiration) or SolveSpace better?
Neither clearly leads. MoI (Moment of Inspiration) starts at On request and SolveSpace at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, MoI (Moment of Inspiration) or SolveSpace?
SolveSpace has a free tier; the other does not. Paid plans start at On request for MoI (Moment of Inspiration) and Free for SolveSpace.
Does MoI (Moment of Inspiration) or SolveSpace run on more platforms?
MoI (Moment of Inspiration) runs on Windows, macOS. SolveSpace runs on Windows, macOS, Linux.
Can I use SolveSpace for free?
Yes. SolveSpace has a free tier, so you can try it without paying. MoI (Moment of Inspiration) starts at On request.
What is MoI (Moment of Inspiration) best used for?
MoI (Moment of Inspiration) is most often used for converting cad surfaces into clean quad meshes for a polygon or sculpting application, modelling hard-surface concept designs where form matters and engineering documentation does not, working on older or low-specification hardware that will not run mainstream cad, buying a modelling tool outright rather than committing to a recurring cad subscription. Of those, converting cad surfaces into clean quad meshes for a polygon or sculpting application and modelling hard-surface concept designs where form matters and engineering documentation does not are not what SolveSpace is typically brought in for.
What can MoI (Moment of Inspiration) do that SolveSpace cannot?
MoI (Moment of Inspiration) covers Direct NURBS modelling, Clean mesh export, Pen-oriented interface, Boolean toolset. SolveSpace covers Constraint solver, Solid modelling, Assemblies, Export formats.

Answered from the vendors’ own pages

MoI (Moment of Inspiration): Is it a subscription?

No. It is bought outright per major version, and each new major version is a separate paid upgrade.

SolveSpace: Is it really free for commercial work?

Yes. It is released under the GPL with no licence fee and no seat limit. Support is community only.

MoI (Moment of Inspiration): Can it replace Rhino?

For direct form modelling, often yes. For anything needing Grasshopper, drawings, plugins or engineering interoperability, no.

SolveSpace: Can it replace Fusion 360 or SolidWorks?

No. It handles parts and simple assemblies well. Complex geometry, drawings and supply chain interoperability are outside its range.

MoI (Moment of Inspiration): Why do 3D artists use it alongside other tools?

Its NURBS to polygon conversion produces cleaner meshes than most CAD exporters, which saves retopology work downstream.

SolveSpace: What hardware does it need?

Very little. It runs on old laptops and small Linux machines where mainstream CAD will not start.

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