Question for cad users

[maybach_man]

Hi all... When you do your dawings whether 2d or 3d do you do them at actual full size so you can scale them to any size? or do you draw at the scale you will be modelling?

 

Thanks

[bootneck]

Hello maybach,

 

I should imagine that we all do things differently, such as full size and to scale.   Full size is good, should you wish to produce/print differently scaled versions; however, some detail can fail to print if you scale down to much.  Likewise, scaling up from a low scale drawing might make some part appear blocky.   I build 1:144 scale models and I usually draw exactly to scale, if I can.  That way, I know what will print and what would fail, which is anything smaller than about 0.25mm thickness.

 

I did a CAD at 1:144 scale of a Queen Mary Trailer and the side frames were 0.3mm thickness.  The trailer, without the Bedford OX is only 83mm long.

 

If I had drawn this at full size then those frames would have failed when scaled down to this size.  So, it's a little of swings and roundabouts.

 

cheers,
Mike

 

[wellsprop]

I design everything in scale, this is because I account for the required printing tolerances.

[maybach_man]

thank you all

[Alvaro Rodriguez]

Just for the record, I also use design in scale always.

 

While rescaling a 1:1 desing to any given scale is not an issue for the software, this is misleading because rescaling from 1:1 can lead to actual printing issues often so that´s not how this works.

 

The problem here is that you can reach printing constrains and the model cannot be printed safely. Details (no matter in positive or negative spaces, like a rivet, a plate or a groove) can be too small, thin or fragile to be printed. So there are some minimun dimensions we should not go below for ensuring our model is printable. Those minimun dimensions will depend not only on if the print is robust enough but on the printer acurracy too.

 

Fact is that this is not unique to 3D printing but to any other manufacturing process applied to scale modelling but we use to think that these tiny -and basic and cheap!- miracle machines have no limits many often ! 😅😆

 

Regards!

Alvaro