# Simple 3D dimensions not printing as designed
**URL:** https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460
**Category:** Modeling Questions
**Created:** [December 20, 2020, 5:18pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460 "2020-12-20T17:18:15Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Bapski](https://discourse.shapr3d.com/u/Bapski)
#### Post date: [December 20, 2020, 5:18pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/1 "2020-12-20T17:18:15Z")
Hello everyone! My first post and foray in 3D design.
I designed a simple headset spacer 15mm high about 34mm OD and 26mmID but when i printed it it was way bigger than the dimensions i drew. What did i do wrong?
Thanksin advance.
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### Author:  [@MrJack88](https://discourse.shapr3d.com/u/MrJack88)
#### Post date: [December 20, 2020, 5:35pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/2 "2020-12-20T17:35:13Z")
@Bapski
It seems like you made a different measurement than mm “cm maybe”
That or you enlarged it on your slicer.
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### Author:  [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)
#### Post date: [December 20, 2020, 5:38pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/3 "2020-12-20T17:38:16Z")
You might be right however if cm vs mm then the final model to print would be 10x size, right?
I’ll wager a guess that the original model was dimensioned with a ‘diameter’ measurement when a ‘radius’ dimension was needed. Just a guess.
-Mike
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### Author:  [@Bapski](https://discourse.shapr3d.com/u/Bapski)
#### Post date: [December 20, 2020, 5:38pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/4 "2020-12-20T17:38:34Z")
I used prusa slicer and i don’t i changed anything. I just thought i changed a setting or so.
I will try again later. Thanks
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### Author:  [@MrJack88](https://discourse.shapr3d.com/u/MrJack88)
#### Post date: [December 20, 2020, 5:38pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/5 "2020-12-20T17:38:56Z")
Ooh wait a minute!!
Sure you did not made a circle and made the OD 34mm… Right?
Because that’s a radius…
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### Author:  [@Bapski](https://discourse.shapr3d.com/u/Bapski)
#### Post date: [December 20, 2020, 5:39pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/6 "2020-12-20T17:39:11Z")
This could be it…
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### Author:  [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)
#### Post date: [December 20, 2020, 5:46pm UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/7 "2020-12-20T17:46:40Z")
This brought back some memories. Decades ago I made the radius vs diameter dimension mistake. I designed some headphones for Big Jim and the parts came out way too big. Luckily the parts were not production parts but rather engineering samples. Guess what, I never made that mistake again!!!
-Mike
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### Author:  [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)
#### Post date: [December 21, 2020, 3:42am UTC](https://discourse.shapr3d.com/t/simple-3d-dimensions-not-printing-as-designed/10460/8 "2020-12-21T03:42:23Z")
No, smaller. It scales the cm down mm. If I’m working in inches my part imports into slicer teeny tiny. You have to change the scale to mm.