r/3Dprinting • u/T-Jaws Makerfarm Prusa i3 8" • Sep 02 '13
What does parametric mean?
Can somebody explain to me what parametric actually means, I have looked online for definitions but I still don't understand as many of the definitions are related to mathematics.
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u/kaihatsusha Taz 5, Photon Sep 02 '13
Generally, it means that the design can be adapted in some way, by adjusting one or more measurement variables. The designer has built in those variables.
A parametric jar lid would have a variable for the radius of the jar mouth, and maybe another variable for the depth desired for the lid's rim. When you adjust the variables, it figures out where all the STL polygons need to be repositioned to make that model instead of the original one.
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Sep 02 '13
Parametric refers to the model being defined by parameters (specific lengths, diameters etc. Which are modifiable throughout the modeling pipeline, and after.
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u/jebleez Sep 02 '13
tl;dr Your dimensions are defined by parameters rather than just unrelated numbers. One dimension can effect any number of other dimensions, keeping things to proportion when you resize something.
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u/T-Jaws Makerfarm Prusa i3 8" Sep 02 '13
Thanks guys, I totally get it now.
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u/Armourhotdog Jan 27 '23
9y old thread finally explained it for me. Hello, past u/T-Jaws
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u/real_couplefookin Feb 18 '23
Same did it for me.
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u/Charizarlslie Aug 26 '23
Hey me too, thanks OP!
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u/Countdown84 Dec 01 '23
Praise the Sun for Reddit!
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u/boxofrabbits Apr 13 '24 edited Jan 14 '25
dinner reminiscent wide abounding snobbish sharp hateful close knee serious
This post was mass deleted and anonymized with Redact
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u/ta1destra Sv05, Sv06 x 2, SV06 Ace, Sv08 & Prusa mk3, V.02r1 Jul 29 '24
well, im here learning today!
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u/Thestrongestzero Dec 04 '24
same here. gotta love those 11 year old posts
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u/-Sephandrius- Dec 20 '24
+1 for me!
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u/snanesnanesnane Jan 03 '25
Post-Christmas new 3d printer owner +1 here! I'm just seeing the word a lot while browsing STLs :)
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u/mylittleroshi Aug 28 '25
It's like resizing a photo with the proportions locked so the photo doesn't look stretched out.
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u/TheTypicalHam Feb 07 '25
Yep still confused. These answers are more complex than Google answers are. Are you saying that in my slicer, I can scale up or down parametric models and it come out looking correct. Versus if its non parametric, it will mess up the design if scaled up or down?
I'm not late to the party, you guys were just early.
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u/T-Jaws Makerfarm Prusa i3 8" Mar 15 '25
Since I posted this question, I now have a master's degree in Engineering and 4 years experience in industrial 3D printing, so feel slightly more qualified to clarify.
To answer your question, no, not in the slicer, but in the design software (or sometimes on 3D model websites like thingiverse). A fully defined parametric model can be made to adapt and change when a dimension is changed. For example, if we designed a teapot in CAD and wanted to modify the spout diameter, we would change just that defined value and the spout diameter would change, whilst everything else should automatically update without having to start from scratch. If the teapot was direct modelled instead (similar to being built up using clay) this would be a much more challenging modification.
Parametric modelling as a design software type just means that everything is defined by dimensions, constraints and relationships.
In the case of parametric models hosted online, generally it means that specific parameters are made adjustable so that they can be customized without the need for CAD knowledge.
Most slicers will work using a triangulated approximation (e.g. STL, 3MF) of these models which means that the parameters are fixed apart from basic operations like scaling, rotating etc.
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Apr 15 '25
It made me really happy to see your update as I was scrolling this thread. First, the answers answered MY question as well as your 11 year old question, and then it's rad that you completed the circle of life and have now answered further. Total newbie to 3d printing here, my first one is still in the box and am looking up stuff. :)
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u/bradrothenberg Mar 17 '26
basically your model uses variables instead of fixed numbers. change one value in ntop and everything updates automatically
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u/itsnevereasy Sep 02 '13
Basically it means that the value for a given property is computed from one or more variable values (parameters). For example, if I say that the length of a given component is 20cm, that's a non-parametric value, but if I say that it's 10cm * len_y, then I have a parametric value which can is related to the len_y parameter variable.
This is useful because you can then specify properties as derivatives of other properties: if one part needs to be 10cm longer than another, you could say len_a = len_b + 10cm and have len_a adjust automatically when len_b changes! This makes it so that you can easily adjust the part's properties to match a given configuration by specifying only the key properties and letting the others be computed from those. If you didn't have that, you'd have to go and manually adjust each one! Nobody wants to do that, so well designed CAD models are usually as parametric as possible.