[SOLVED!] 3DS Max - How to export a UVW map to be the same size as the object would be IRL?

Roxirin

EDIT: I found a solution! Not exactly by anoyone's suggestion, but in the end I did as follows: I selected the whole object and applied the 'UWV Map' modifier to it (making sure my world units/unit setup was 1 unit=1cm and that the model was the correct size). I ticked 'real-world scale' in the 'scale' part of the sidebar, and set the unwrap projection type to 'plane' (this didn't really matter since I was going to manually unwrap it anyway). I collapsed that modifier and applied a 'Unwrap UWV' modifier. I then scaled the whole UWV island down to 1% of its original size (enter 1 in the scale box and make sure you're maintaining aspect ratio between x y and z) so that it would fit in the UV tile (which was equal to 1cm). I unwrapped the object as normal (in a way which would work best when sewing the object IRL), but only using the 'quick peel', 'relax until flat', and 'stitch' options (with 'avoid overlap' turned off in quick peel settings) so that none of the islands would change size, just shape. Finally, I arranged everything and exported it onto a 1024x1024 png.

I took it into my editing program (Clip Studio Paint, but you could use Photoshop or whatever), and changed the DPI of the image to '300'. 3ds Max exports at 72 DPI, so setting the DPI to 300 scales the image back up to the correct 'real life' size.

Then I just saved it, pulled it into MS paint, told it to print to '100% of real size' in the page setup print setting, and hit print! Pattern printed and ready to be transferred onto fabric I'll update with the final product for proof of concept!

Thanks for everyone's advice!

This one's probably pretty niche, so thanks in advance if you decide to take on the uh.. interesting task of helping!

Here's the rundown:

1) I made a boot in 3DS Max (It's Yoshi's boot!). The boot is, in Max, a size of 18 x 32 x 21 cms.

2) I unwrapped the boot into pieces that would work/fit together if I made the boot IRL out of fabric and toy stuffing.

3) I now want to export the UWV maps so that I can print them out the same size as the boot is in 3DS max. So the pattern pieces would form a boot IRL that is 18 x 32 x 21 cms.

4) Please god, how the fuck do I do that?

I've gotten as far as figuring out that I can print an image the exact size that the image actually is by using MS paint (rather than any other program trying to resize it to fit on the page), so that part's not a problem. The problem is that I don't know how to export a UVW map in a way that makes it the same size as the IRL dimensions.

Any help on this is incredibly appreciated, and you will be rewarded handsomely with a bounty of 'omg thank you so much you're the fuckin best I love you'

poopipe

you need to worry about texel density  - you also need worry about distortion (a lot) 

unfortunately max doesn't have a texel density tool.  I wrote one, I'm sure others are available

texel density = the size of your uvs in relation to the real world size of  your texture.  There are many threads on here with people getting confused about it but simply put it's worked out by checking the area of your triangles in world space against their size in UV space and then working out how big the UV space is in terms of world space (i.e real world size) 

you have an added complication in that pieces of paper aren't square and are also stupid sizes but you should be able to work that bit out. 

step1 : find a texel density tool for max

step2 : deal with distortion. 
Max has a way to visualise UV distortion - it's not great but it's better than nothing.   Use that and  add splits until your UVs stop being distorted - with fabric you can probably deal with a bit of stretching, with paper you definitely can't. 

you can probably split at the back of the shoe and pelt map the main body to eliminate most of the distortion, it'll probaly take a few tries to get right

Klunk

this script will turn the uvs into geometry which maybe more useful for you

open it in maxscript editor and with the boot selected press ctrl-e.... then you can scale to match the boot convert the border edges into spline shapes and export those to package that can print to size ?

FrankPolygon

As has already been mentioned: the big thing is to try and limit the amount of distortion in the unwraps. Rounded or spherical shapes will likely require a lot of seams for the physical material to sit correctly when it's stitched together. It may be worth looking at examples of boot patterns to get a basic idea of the most efficient way to place the seams on the model and cut out the fabric. Also remember to account for the seam allowance around the individual pieces of the pattern.

A square plane with a known dimension can be unwrapped and used as a scaling reference if the size of all the UV islands is averaged. Once the UV sheet is exported the image can be scaled up until the reference square is the correct size in the image editing software. Individual UV islands can then be moved around and printed at 1:1 scale.

Here's an example that shows how the seams can be placed on the model so the unwrap mimics a traditional boot pattern layout with a sole, vamp, upper and collar. With this seam layout the model should unwrap with minimal distortion.

All of the UVs have the same averaged scale and the reference square is 10x10cm so the whole UV sheet can be scaled up or down and the only thing that needs to be measured in the image editing software is the size of the reference square. The orange outline around the UV islands is the seam allowance, which can be generated procedural by adding an outside stroke effect to the UV islands.

Another option would be to use dedicated pattern making software like Pepakura Designer or PaperMaker.

Roxirin

poopipe said:

you need to worry about texel density  - you also need worry about distortion (a lot) 

unfortunately max doesn't have a texel density tool.  I wrote one, I'm sure others are available

texel density = the size of your uvs in relation to the real world size of  your texture.  There are many threads on here with people getting confused about it but simply put it's worked out by checking the area of your triangles in world space against their size in UV space and then working out how big the UV space is in terms of world space (i.e real world size) 

you have an added complication in that pieces of paper aren't square and are also stupid sizes but you should be able to work that bit out. 

step1 : find a texel density tool for max

step2 : deal with distortion. 
Max has a way to visualise UV distortion - it's not great but it's better than nothing.   Use that and  add splits until your UVs stop being distorted - with fabric you can probably deal with a bit of stretching, with paper you definitely can't. 

you can probably split at the back of the shoe and pelt map the main body to eliminate most of the distortion, it'll probaly take a few tries to get right

Thanks for your answer - I'm sorry, I should have mentioned that I did already get this far XD I have a texel density tool and the distortion was looking more or less fine when i unwrapped it, so that's good at least. Thanks all the same!

Roxirin

Klunk said:

this script will turn the uvs into geometry which maybe more useful for you

open it in maxscript editor and with the boot selected press ctrl-e.... then you can scale to match the boot convert the border edges into spline shapes and export those to package that can print to size ?

Thanks for the script - I'll give it a go!

Roxirin

FrankPolygon said:

As has already been mentioned: the big thing is to try and limit the amount of distortion in the unwraps. Rounded or spherical shapes will likely require a lot of seams for the physical material to sit correctly when it's stitched together. It may be worth looking at examples of boot patterns to get a basic idea of the most efficient way to place the seams on the model and cut out the fabric. Also remember to account for the seam allowance around the individual pieces of the pattern.

A square plane with a known dimension can be unwrapped and used as a scaling reference if the size of all the UV islands is averaged. Once the UV sheet is exported the image can be scaled up until the reference square is the correct size in the image editing software. Individual UV islands can then be moved around and printed at 1:1 scale.

Here's an example that shows how the seams can be placed on the model so the unwrap mimics a traditional boot pattern layout with a sole, vamp, upper and collar. With this seam layout the model should unwrap with minimal distortion.

All of the UVs have the same averaged scale and the reference square is 10x10cm so the whole UV sheet can be scaled up or down and the only thing that needs to be measured in the image editing software is the size of the reference square. The orange outline around the UV islands is the seam allowance, which can be generated procedural by adding an outside stroke effect to the UV islands.

Another option would be to use dedicated pattern making software like Pepakura Designer or PaperMaker.

Oh wow - this is a very detailed answer, thank you! I'm also pretty floored by your image - did you just draw over it, or did you straight up just go and model the thing yourself to demonstrate? Either way that's insanely cool of you, thank you so much for your time and effort!! :000

The dimension square thing is actually a really good idea - thank you! I'll give it a go and report back with my findings Also never knew about the 'seam allowance' capabilities of Max, either - neat! I'm getting the feeling you've done this before...

I tried Pepakura, but it seems like it was very unhappy with my 'highpoly' mesh and tried to put seams on every single mesh line. I hadn't used it before and couldn't figure out how to change it without pouring hours into it so I went back to Max I feel like it's better for more 'angular' things, unless I'm mistaken?

FrankPolygon

@Roxirin Glad it was helpful. The sample model was a quick way to help illustrate the process. Just to clarify: seam allowance in a sewing term and the orange outline around the UV islands was added in Photoshop. After the model is unwrapped and the UV scale is averaged out it kind of makes sense to do the rest of the work in a dedicated image editing program since it's going to be faster and there's a lot more control over print options.

Pepakura can handle a reasonable amount of polygons but there's also a certain convenience factor to having a model that's been created with paper craft and pattern making in mind. This video is a decent overview of the process and explains how a simplified model can be used to develop the patterns.

https://youtu.be/vRrfclFDiS0

Coming from a 3D studio arts and textiles background: EVA foam is it's own thing but there's going to be similar considerations for sewing fabric together. If the end goal is to create physical objects with fabric and stuffing it's probably worth taking some time to look up a couple videos on sewing patterns for similar objects.

https://youtu.be/J0FCr1V6SNc

Polyester felt might be a good material choice for testing the pattern. It's relatively cheap, doesn't unravel like woven textiles and is pretty forgiving to work with. It is possible to glue fabric together but it's messy and doesn't tend to have the longevity of properly sewn seams.

Right now it looks like you have a fairly decent start with the existing model. Just need to work out the seam placement and get the UV islands into a printable format. From there it should be fairly easy to add the seam allowance, scale things up, print and cut out the test pattern.