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Software · head to head

Principle vs Spline

P

Principle

Software

Animate your ideas, design better apps

From
$129/one-time
Rated
-
Full reviewWebsite
Spline logo

Spline

Software

3D design tool for the web

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Spline has a free tier, so it costs nothing to try first.
  • Each has a real cost: Principle macOS only with no Windows or Linux editor available; Spline aI generation features produce inconsistent and often distorted results, failing at basic depth perception tasks
  • They diverge on capability: Principle covers Timeline-based animation, Spline covers 3D modeling.

Where they differ

Only the attributes on which Principle and Spline actually diverge.

Attributes where Principle and Spline differ
AttributePrincipleSpline
Starting price$129/one-timeFree
Pricing modelUnknownfreemium
Free tierNoYes
PlatformsmacOSWeb, iOS, Android, visionOS
Founded20152020

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

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 Principle

  • Timeline-based animation
  • Interactive prototypes
  • Touch gestures
  • Component reuse
  • Video export
  • Sketch import
  • Figma import
  • Driver animations

Only in Spline

  • 3D modeling
  • Real-time collaboration
  • Animations
  • Interactions
  • Code export
  • React
  • Next.js
  • Webflow

What people use each for

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

Principle

  • Mobile app prototypesnot Spline
  • Micro-interactionsnot Spline
  • Animation designnot Spline
  • User flow designnot Spline
  • Gesture-based interfacesnot Spline

Spline

  • Web 3D experiencesnot Principle
  • Interactive prototypesnot Principle
  • Product visualizationnot Principle

Where each one falls short

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

Principle

  • macOS only with no Windows or Linux editor available
  • No vector morphing capability for complex shape transformations
  • Limited asset creation tools; cannot create vectors or shapes directly within Principle
  • Sketch import flattens certain properties including paths, fills, borders, masks, blur effects, and text layers
  • Limited variable support, logical loops, and data input capabilities compared to tools like ProtoPie or Origami

Spline

  • AI generation features produce inconsistent and often distorted results, failing at basic depth perception tasks
  • Limited to simpler designs - not suitable for high-poly, detailed production models
  • Performance degrades with complex scenes containing many objects and materials
  • Limited non-Apple platform coverage compared to cross-platform design tools
  • Tutorials are either too fast for beginners or too basic for advanced users

Pricing, plan by plan

Principle

$129/one-time
  • License$129/one-time
    • One year of upgrades
    • Full access to all features
  • Upgrade License$99/year
    • Annual renewal for ongoing upgrades

Spline

Free
  • FreeFree
    • Unlimited projects
    • Basic exports
    • Community support
  • Pro$9/month
    • Advanced exports
    • Custom domains
    • Password protection
  • Team$19/month
    • Team collaboration
    • Version control
    • Admin controls

Which should you pick?

Choose Principle if

  • You need timeline-based animation.
  • You work on macOS.
  • You also want interactive prototypes.
Principle review

Choose Spline if

  • You need 3d modeling.
  • You want to start without paying.
  • You work on Web, iOS, Android, visionOS.
  • You also want real-time collaboration.
Spline review

Questions people ask

Is Principle or Spline better?
Neither clearly leads. Principle starts at $129/one-time and Spline at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Principle or Spline?
Spline has a free tier; the other does not. Paid plans start at $129/one-time for Principle and Free for Spline.
Does Principle or Spline run on more platforms?
Principle runs on macOS. Spline runs on Web, iOS, Android, visionOS.
Can I use Spline for free?
Yes. Spline has a free tier, so you can try it without paying. Principle starts at $129/one-time.
What is Principle best used for?
Principle is most often used for mobile app prototypes, micro-interactions, animation design, user flow design. Of those, mobile app prototypes and micro-interactions are not what Spline is typically brought in for.
What can Principle do that Spline cannot?
Principle covers Timeline-based animation, Interactive prototypes, Touch gestures, Component reuse. Spline covers 3D modeling, Real-time collaboration, Animations, Interactions.

Answered from the vendors’ own pages

Principle: Does Principle run on Windows or Linux?

No. Principle is macOS only and runs on Intel and Apple Silicon Macs. There is no Windows or Linux editor available; however, prototypes can be shared and viewed on any platform via web link.

Source
Spline: What is Spline's pricing?

Spline offers a Free plan with watermarked web exports, Starter at $12/month (billed annually) removing watermarks, Professional at $20/month with unlimited projects, and Enterprise with custom pricing. Viewers are unlimited on all plans.

Source
Principle: What is the cost of Principle?

Principle costs $129 for a one-time purchase with 1 year of upgrades included. After 1 year, upgrade licenses cost $99/year. A 14-day free trial is available with all features included.

Source
Spline: Can Spline export 3D models to other tools?

Spline's export/import format support is more limited compared to traditional 3D tools like Blender. It focuses on web-first exports and native app code generation.

Source
Principle: Can I import designs from Figma or Sketch into Principle?

Yes. Principle supports importing designs from Figma and Sketch with intelligent merging of re-imported files. Some Sketch properties such as paths, fills, borders, blur effects, masks, and text layers are flattened upon import.

Source
Principle: How do I share Principle prototypes with others?

Prototypes can be shared via web link with one click (File > Export > Share to Web). Recipients can view and interact with prototypes in any browser on any platform: Windows, macOS, Linux, Android, or iOS. No installation required.

Source
Principle: Can I create vector shapes and morphing animations in Principle?

Principle does not support vector morphing, where vector objects transform into other vector shapes. It also has limited asset creation capabilities and editing is restricted to basic operations like scale and rotate.

Source
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