cloth textures in normal map

[garethcowboy]

Hi everyone
I've seen tons of great low poly model having cloth textile detail on the cloth surface(in fact I thought it's pretty much a basic thing), but when I start to do it I was kind of lost.
I was making a pair of jeans- I scupted the wrinkle of the cloth in zbrush(highRes model of course) and generated the normal map for the low poly, and made the denim's textile detail bump map in photoshop. But how can I compose the textile map on top of the wrinkle normal map?
I know some people scuple textile details right on the highRes model using alpha brushes, but I can't affort to have that polycount so I have to use seperate bump maps.
The only way I can think of is to multiple-layer the bump map on top of the wrinkle normal map and then normalize the whole thing, but then the low poly's shading got all weird(apeared a lot darker), and not to mention it messed up the seams.
It may be something very basic but I really got stuck here so please help. Thanks heaps in advance.

[Codeman]

You might try CrazyBump as it allows you to combine multiple normals and output a single file.

[garethcowboy]

Thanks! I'll try crazyBump and see how is the result

But is there a more generic way to do that? I mean, are all the good textures made by scupting all the cloth detail on the mesh? Sounds like really a lot of work to me...

[Codeman]

In my experience it really depends. For a heavy weave yes, sculpted in. For a fine fabric do it in psd or crazybump. I am no expert on fabric though.

[Nizza_waaarg]

after making your heightmap/bumpmap with the detail, you can just set it as an overlay layer over your normal map in photoshop. Might have to play with the rgb channels a little is all (i think you have to remove the blue channel so it doesn't mess with the depth, but make sure you're using overlay on the layer is the most important part).

You can use crazybump or the free nvidia normal map filter to get your normal map from the height or bump map btw.

[garethcowboy]

Wow thank you so much nizza! I used overlay and it just worked!
(should have played with something more than multiply at the begining)
the shading is correct now, and most importantly it won't mess with the UV seams! just what I wanted! Thank you nizza again!
However if I remove the blue channel in the fabric bump the seams showed up...probably need more tweaking, but overlay alone seems working just fine.
ps. crazybump is awesome!..

[The Devo]

Make sure when you do the overlay that you remove the blue channel. Go into 'levels' on that layer, drop down the "blue" channel, and set the output level to 128. The layer should turn grey. That will prevent the blue from diluting the layer underneath. If you find that the cloth layer is a bit too subtle, you can just duplicate it and adjust the opacity to suit your tastes.

Chris

[garethcowboy]

Thank you Devo
though I dont quite get it that you say set output level to 128-are you refering something in photoshop? and what will be the problem if I dont adjust the blue channel?
I simply overlayed the fabric normal map onto the wrinkle normal map and it seemed to work fine, but I'm interested in the blue channel thing too, as I know it's the depth info-if I understand normal map correctly, and If I do anything to it(delete or adjust level) in photoshop then the entire map's uv boarder goes wrong and the sharp seam will show up on the low poly.
ps. what I did is
1.get wrinkle normal map from sculpted high mesh
2.get denim fabric photo and desaturated it and normalize it using nVIDIA filter
3.overlay the fabric normal map onto wrinkle normal map.
that works fine. curious about the blue channel though.

[MM]

you dont need to normalize anything if you have a high res normal map. at least i never ever had to. however i never use crazybump though.

anyways, to create a decent bump of the fabric texture u can use filter - high pass on the fabric color texture, desaturate and use the nvidia filter to create a normal off of it.

then fill 50% black to the blue channel of this fabric normal map. (same as what Devo mentioned)

put this fabric normal map on top of the high res normal map using overlay blending mode.

if you dont add the 50% black to the overlay normals then your final normal map wont have proper depth info from the high res normal map.

[garethcowboy]

Roger~ learnt alot from the replies Thanks!

[JacqueChoi]

This is my method:

Here's a Normal Map Pallette I made by Projecting stuff in Max (gawd, made this 3 years ago when I was making accessories for skaters in Tony Hawk):

(I think I Flipped the Red Channel for use in Maya, so it might be inverted along the Tangent Space X-Axis)

So what I do is I swab the 2 complimentary diagonal colours (Purple and Pink), and paint an entire texture sheet in only ONE direction.

(ClothTexture_01.jpg, and ClothTexture_02.jpg)
With ClothTexture_01.jpg I will rotate it exactly 45degrees.

After I bake my Normal Maps, I will throw one of these into an OVERLAY layer in photoshop, then reduce its opacity to under 25% (usually 10-15% will do). Then erase all the areas I don't want to have cloth texture.

Horray for Ultra Crisp Cloth Textures in Normal Maps!

The Painted Normal Map - Overlay Technique is fantasic for pixel-painting double stitch seams, and all kinds of fun little details.


It's a much different aesthetic, that goes better with a more stylized-paintery look. The above mentioned post is fantastic for a more realistic aesthetic.

[garethcowboy]

That result is really cool looking! Thanks for sharing that process too!
definitely will try that~