<h1>Use a CAD software</h1>
<p>Whenever you need to make a part fit given dimensions, it is best to set those. There are tons of <a href="https://en.wikipedia.org/wiki/Computer-aided_design" rel="nofollow noreferrer">Computer Aided Design</a> software packages around, starting at free and ending at thousands a year for a single PC license. There are so many, that <a href="https://en.wikipedia.org/wiki/Comparison_of_computer-aided_design_software" rel="nofollow noreferrer">Wikipedia made a comparison list</a></p>
<p><a href="https://all3dp.com/1/best-free-cad-software-2d-3d-cad-programs-design/" rel="nofollow noreferrer">all3Dp</a> always curates a list of free 3D software. Among them, I can point to the following as options:</p>
<ul>
<li>I personally prefer Fusion 360 by Autodesk, which is quite powerful but slightly cut down in the free version. It is known to produce very good exportable designs but has a somewhat steep learning curve. It also allows parametric designs, very valuable if you need to customize items.</li>
<li>Onshape is similar to Fusion 360 in that Hobbyists get it free, but it is browser-based, making it possibly easier accessible. It is a full-powered CAD suite, including parametric design.</li>
<li>FreeCAD might not be as powerful or fancy as Fusion360 and Onshape, but it is a solid, well-working CAD package. It has also a somewhat easier learning curve than the likes. It allows entering OpenSCAD code, which means, you can add mathematic formulae to design your part.</li>
<li>OpenSCAD is the absolute barebone, but absolutely parametric. It takes mathematical descriptions of bodies to design them - which is hard to learn and master but allows to create some very intricate mathematical models.</li>
<li>SketchUp Free has a dubious reputation among printing enthusiasts, as its STL solutions at times have inverted surfaces.</li>
</ul>
<p>Not on the curated list of all3dp is one entry I personally worked with and which is somewhat potent but easy to use:</p>
<ul>
<li><a href="https://www.rs-online.com/designspark/mechanical-software" rel="nofollow noreferrer">DesignSpark Mechanical</a> is a derivative of the powerful Ansys Space Claim CAD software and is offered for free. It is <em>somewhat</em> limited though.</li>
</ul>

CC BY-SA 4.0
2022-05-09T09:21:54.180Z
2022-05-09T09:21:54.180Z
Trish
<p>Use software specifically designed for making parts with specific dimensions and then measure exactly what you need and design from the measurements.</p>
<p>I use Freecad for this sort of thing but there are plenty of others that let you precisely control the measurements.</p>
<p>Most 3d software could probably manage it, but if you use one specifically designed for this sort of work there is less of a learning curve and you don't have to mess around learning irrelevant stuff.</p>

CC BY-SA 4.0
2022-05-08T18:21:27.927Z
Basically any engineering cad package would work.  OpenSCAD, fusion360, freecad, others that are not free..
user10489
CC BY-SA 4.0
2022-05-08T18:25:17.700Z
My average record for doing this sort of thing is to measure carefully it but still have to print 3 prototype parts and tweak dimensions each time to get it to fit.
user10489
CC BY-SA 4.0
2022-05-08T22:11:06.727Z
@user10489 I have better luck I guess, it usually works first time for me. But I'm an engineer so I'm used to fabricating things. And I drill holes and things rather than print them.
Kilisi
CC BY-SA 4.0
2022-05-09T01:11:45.207Z
You have better luck or your printer is better calibrated or you are less picky.   :)  Sometimes I drill holes (or make them bigger), and then fix them when I find a second dimension that isn't perfect.
user10489
CC BY-SA 4.0
2022-05-09T02:23:13.143Z
Any pros/cons in what software to select?
when squared equals a negative
CC BY-SA 4.0
2022-05-09T09:24:53.753Z
Pros and cons are really about what you want to do long term. If you won't be using it much pick something basic without a big learning curve. If you think you'll be doing a lot of part design then go for something more comprehensive. Just check the reviews on the software.
Kilisi
CC BY-SA 4.0
2022-05-09T09:32:15.290Z
@user10489 it's just plastic, if I'm in doubt I'll print a section bigger than I need and cut or file it down. Heat and bend it or whatever. Not interested in printing 3 prototypes, thats just a waste of resources and time.
Kilisi
CC BY-SA 4.0
2022-05-08T07:58:11.573Z
2022-05-08T07:58:11.573Z
Kilisi
<p>Looking to print a new part for a home appliance. There's going to need to be a new model created with the customizations made, but the model (after printing) will have to fit where the old part was. Is there any 3D modeling software that is better for this purpose? Will I just have to guess at proper proportions and hand-adjust the scaling of each dimension and angle through trial and error until a version fits?</p>

CC BY-SA 4.0
2022-05-11T02:34:04.540Z
You can usually measure most dimensions with a digital caliper and enter them as parameters into your model. But curves, angles and such are more difficult to get right. I often print small sections or slices of my whole model to check for fit against existing parts. For example in PrusaSlicer you can cut a model into pieces with a few clicks, and then only print the part that requires “verification in print.” This way you waste minimal amounts of time and filament, and can be relatively certain that the big, final part fits on first attempt.
Christoph
<3d-models><rapid-prototyping>
Best way to make a new model for custom part printing?
when squared equals a negative
# Best way to make a new model for custom part printing?

(Asked by: username_0 on 2022-05-08)

Looking to print a new part for a home appliance. There's going to need to be a new model created with the customizations made, but the model (after printing) will have to fit where the old part was. Is there any 3D modeling software that is better for this purpose? Will I just have to guess at proper proportions and hand-adjust the scaling of each dimension and angle through trial and error until a version fits?

**Tags:** 3d-models, rapid-prototyping
> **Comments:**
> **username_1**: You can usually measure most dimensions with a digital caliper and enter them as parameters into your model. But curves, angles and such are more difficult to get right. I often print small sections or slices of my whole model to check for fit against existing parts. For example in PrusaSlicer you can cut a model into pieces with a few clicks, and then only print the part that requires “verification in print.” This way you waste minimal amounts of time and filament, and can be relatively certain that the big, final part fits on first attempt.  

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## 2 answers

### Answer by username_3 on 2022-05-08. Score: 2 | Accepted answer

Use software specifically designed for making parts with specific dimensions and then measure exactly what you need and design from the measurements.

I use Freecad for this sort of thing but there are plenty of others that let you precisely control the measurements.

Most 3d software could probably manage it, but if you use one specifically designed for this sort of work there is less of a learning curve and you don't have to mess around learning irrelevant stuff.

> **Comments:**
> **username_4**: Basically any engineering cad package would work.  OpenSCAD, fusion360, freecad, others that are not free..  
> **username_4**: My average record for doing this sort of thing is to measure carefully it but still have to print 3 prototype parts and tweak dimensions each time to get it to fit.  
> **username_3**: @user10489 I have better luck I guess, it usually works first time for me. But I'm an engineer so I'm used to fabricating things. And I drill holes and things rather than print them.  
> **username_4**: You have better luck or your printer is better calibrated or you are less picky.   :)  Sometimes I drill holes (or make them bigger), and then fix them when I find a second dimension that isn't perfect.  
> **username_0**: Any pros/cons in what software to select?  
> **username_3**: Pros and cons are really about what you want to do long term. If you won't be using it much pick something basic without a big learning curve. If you think you'll be doing a lot of part design then go for something more comprehensive. Just check the reviews on the software.  
> **username_3**: @user10489 it's just plastic, if I'm in doubt I'll print a section bigger than I need and cut or file it down. Heat and bend it or whatever. Not interested in printing 3 prototypes, thats just a waste of resources and time.  

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### Answer by username_2 on 2022-05-09. Score: 2

# Use a CAD software

Whenever you need to make a part fit given dimensions, it is best to set those. There are tons of [Computer Aided Design](https://en.wikipedia.org/wiki/Computer-aided_design) software packages around, starting at free and ending at thousands a year for a single PC license. There are so many, that [Wikipedia made a comparison list](https://en.wikipedia.org/wiki/Comparison_of_computer-aided_design_software)

[all3Dp](https://all3dp.com/1/best-free-cad-software-2d-3d-cad-programs-design/) always curates a list of free 3D software. Among them, I can point to the following as options:

* I personally prefer Fusion 360 by Autodesk, which is quite powerful but slightly cut down in the free version. It is known to produce very good exportable designs but has a somewhat steep learning curve. It also allows parametric designs, very valuable if you need to customize items.
* Onshape is similar to Fusion 360 in that Hobbyists get it free, but it is browser-based, making it possibly easier accessible. It is a full-powered CAD suite, including parametric design.
* FreeCAD might not be as powerful or fancy as Fusion360 and Onshape, but it is a solid, well-working CAD package. It has also a somewhat easier learning curve than the likes. It allows entering OpenSCAD code, which means, you can add mathematic formulae to design your part.
* OpenSCAD is the absolute barebone, but absolutely parametric. It takes mathematical descriptions of bodies to design them - which is hard to learn and master but allows to create some very intricate mathematical models.
* SketchUp Free has a dubious reputation among printing enthusiasts, as its STL solutions at times have inverted surfaces.

Not on the curated list of all3dp is one entry I personally worked with and which is somewhat potent but easy to use:

* [DesignSpark Mechanical](https://www.rs-online.com/designspark/mechanical-software) is a derivative of the powerful Ansys Space Claim CAD software and is offered for free. It is *somewhat* limited though.


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