[HowTo] Fine tuning of Pepakura foam parts' size.

These last days, while building from measurements, I encountered a singular issue about the correct scaling of an Iron Man mk4/6 leg.

The quandary was :
If I built a well-scaled leg in height, the top of the thigh was too tight. If I scaled it wider, the leg was too long. If I scaled differently thigh and shin, in order to get the good lenth and the good width, the knee could not clamp properly... :facepalm So, instead of extracting back the original model to stretch it on my own and re-unfold it back (that could be workable but boring), or building it too narrow and adding afterward some foam extentions (that could be workable but unclean), I decided to take the easyest shortcut.

How to enlarge the top of this thigh while keeping the original knee proportions.



The trick is to add the foam extentions before cutting out the foam pieces. To do that, I split the appropriate patterns in two -those that build the top of the part-, leaving a progressive gap on each of the four sides : front back inner outer of the thigh. Progressive, because I want the bottom of the part -the knee- to remain the same size. See it in red :




Then I print, and add the last corrections manualy by drawing some smoother new cutting lines. Here in red :



At the end, the green lines did not change at all, when the red ones allow a larger aperture of the top of the thigh. It takes 10 minutes, is potentially applicable to any part of a suit, and you get an unique custom scaled foam part.

If you use other tips, or have known such a sizing scenario, please share here.

Pictures are broken.... ?!

The host server reboots every wednesday evening... :\

JF your now the BOSS

Very nice tip, JF!

Note that, when using this method, the value of the final enlargement of the aperture is not totally random, but a bit hazardous. Here I first had to set the global scale to 90% because of the knee, and then I needed to grab something like 4 inches in thigh circumference. These 4" are roughly obtained by rule of thumb. So in fact it's not tuned as fine as it pretends to be.

i wish i would've read this before i built the legs lol. once again my friend you hit the nail on the head! that's the exact same problem Ive been running into with sizing the thigh piece on my mk4 build...you bro are a genius! thank you.
- how do you make it split in the program???

also how would you apply this to for example the bicep???

You need to download Pepakura Designer to edit the templates.

To tune a biceps, here are roughly two examples. (Click to enlarge).

- to make it deeper :



- or to make it wider :




You can also make it both deeper and wider, or like the thigh above, wider only neer the shoulder and keep the original size neer the elbow... and so on.

this is way better than the crude method i used on my bicep pieces to make them deeper.


i have pepakura designer...i was wondering as to what command to use to create the progressive split in the tigh file. i tried the join/disjoin face function and it ddnt work. or if the master himself would mind modifying a file for me. but i would like to learn.

Right click, choose Join/Disjoin Face


Cut the patern where you want to extend it.
(note that he tool Join/Disjoin Face also works directly on the 3D view, so you can figure out much better where you are disjoining the template.)


The border of the cuted edge is white, we can't see it :
(but you can drag the template above the grey area to see it better)


choose Edge Color


Tick Hidden Line, select a color (here red), select the paint tool :


Paint the edges :


Choose Rotate


Make it turn in order to get your progressive gap :


You obtain that :


Select and Move


place your parts to match each other


You're done.


This is just a basic step by step about the use of the needed tools. Of course when doing it for real purpose, don't forget to split every pieces you need just like the example few posts above, and to watch out the spacing of the gaps you add.

JF thankyou!