Painting a tire texture and setting up a material for Mental Ray in 3DS MAX
i tend to get questions about the tire mat i used in the above pic, so i decided to share some insights.
first of all you wonīt get a result like this with procedurals or a material you can download somewhere.
To achieve something like the above you need to spend a fair amount of time painting texture maps and tweaking your mat and doing a lot of testrenders.
So, no there is no easy way to get something like that.
So first of all you will have to use a texture, and since there arenīt any (good) tire textures available for free on the net (as far as i know) youīll have to paint one on your own. So start your 2D paint prog (photoshop in my case).
Part 1: Painting a Texture for a tire
Before you open a new document you should think a bit about texture size and whether you want to make a tileable texture or one texture that fits the whole tire
i decided to do a tileable version which looks used but not too worn. Iīll go for a 800x500 map, which should be enough for most of the cases, though you might need a higher res version if you want to do extreme close ups.
to clarify things a bit more: iīm going to paint one texture which covers the sidewalls and the tread area.
1. fill the baselayer with a dark grey.
2. on a new layer insert a texture which provides a basic pattern (feel free to experiment here)
i found a rust texture on this great site.
if there are any visible lighting effects on the texture try to get rid of them by applying a high pass filter (filter->other->highpass). Desaturate the layer (ctrl-shift-u) and set the blending mode to color dodge and reduce the opacity to your liking.
3. insert some other layers of basic textures (fabric or other dirtmaps) and experiment with the blending options and the opacity. for instance i took a fabric texture from the same site scaled it down and put it on top of the rust texture with blending set to multiply.
itīs already looking good
4. another layer of fabric texture, same procedure as step 3 but this time i rotated it 45°
if the texture starts to get too bright or too dark donīt hesitate to tweak the opacity of the underlying layers.
5. now we will add some dust and dirt to the tread area. so i search for another texture with some random patterns that suit this purpose. i stumbled across a asphalt texture which i tweaked a little ( applied a highpass filter and adjusted the levels to make it darker)
then i have centered it, set the blending mode to lighten 10% and added a layer mask.
click the layermask in the layerwindow to switch to this mask. now you can paint in the mask.
set your color to black and set up a custom brush with lots of scattering and check the dualbrush option. try some settings until you get a nice brush.
perhaps something like that:
now paint in the mask to fade out the texture on the right and left side.
the mask should look something like that:
6. keep going with the shown techniques and add layers with different textures, layermasks, blending options.
here is an overview of the layers iīve added:
and here is an overview of the textures i have used:
the high res versions can all be downloaded from http://www.cgtextures.com/
7. now its time to save the result as a tiff, png or whatever you like.
reopen it in photoshop
apply a offset filter (filters>others>offset)
and set the vertical value to 250
now you can use the clone stamp tool and a mid sized brush with a soft falloff to get rid of the seam.
finally you can adjust the brightness and the contrast in case it turned out too bright. but donīt make it too dark because you can always adjust it later in your 3d app.
and finally youīve got your homemade seamless tire texture.
thatīs it for now.
the next part will be about setting up a material in 3dsmax and rendering the tire with mental ray. so stay tuned.
and make sure to post and share the textures you produce after reading this short tut.
p.s.: iīm not going to share the texture iīve made rightaway because i want to encourage you to make your own. But if you guys post several good textures iīm going to share mine as well
CPU Q6600 @ 3GHz Memory 8GB HDD Sansung, Western Digital
Graphics Card AMD Monitor Setup 2x22inch Samsung OS Win7
before you start with the material you should have layed out the uvs propperly and assigned the material ids. i wrote another tut how to map tire so i wonīt do it here again and will just skip this part.
2.1. Basic Lightrig and render settings for testrenders
A good and neutral lighting setup helps adjusting and tweaking the material.
For this purpose iīm using a simple lightrig with one omni and one skylight.
the settings for the omni:
raytraced shadows
intensity: 0,99 color: slightly yellow(ish)
shadow color: very dark blue (almost black)
settings for the skylight:
multiplier: 1
skycolor: light blue
since i always composite the renderings with an ambient occlusion pass, i want the scene to be a bit too bright. if you want to skip the post processing you should lower the intensties a bit.
rendersettings:
Production Renderer: Mental Ray
Finalgather turned on
samples set to 100 (thatīs enough for a preview and even gives some good results if you also use an occlusion pass)
for faster rendering you should use a fixed camera and save the final gather map.
here is what i get with those settings (+ an ambient occlusion pass composited onto it)
2.2 setting up the material:
2.2.1 material type
hit "m" to open the material editor and select an empty slot.
hit "g" and select the "multi/sub-object"
set the number of materials to 2 and select the first one.
2.2.2. Diffuse
change the shading from Blinn to Anisotropic
set the diffuse color to solid black
add a bitmap to the diffuse channel (click the small square next to the color)
load your tread texture
set the map channel to the one youīve set up for the tread (in my case 1)
to preview the textures in the viewport click the checkered cube (tip: "F3" switches the viewports from wireframe to shaded view)
if necessary rotate your texture using the angles in the coordinates section and check the alignment in the viewport
if you are using a tileable texture, raise the value for the tiling until it looks good
if the texture doesnīt line up properly select the uvw mapping modifier for the tread and scale it.
you can see how iīve adjusted the size of the cylindrical gizmo so that the brighter parts of the texture fill the tread area
do a first testrender to see if the brightness of the tread is ok
as you can see itīs too bright so we go back to the bitmap settings and access the output section
reduce the output amount. this reduces the opacity of the bitmap and lets the black color shine through (you also could tweak the color map but thatīs much more timeconsuming)
do a new testrender
and repeat the above steps until youīre fine with it.
2.2.3. Specularity
set the Glossiness to 10
set the anisotropy to 10
drag the map from the diffuse channel into the specular color channel and selcet copy
enter the bitmap settings
go to the output section of the bitmap
invert the map
set the output amount to 1
additionally i have enabled the colormap and raised the upper value to 2 and set the lower to -0.12 to get better highlits
do some testrenders to adjust the setting (tip: to see the effects of your settings you can turn off the diffuse map)
drag another copy of the map from the diffuse channel into the specular level channel (output amunt 1; colormap disabled)
2.2.4. Bump
drag another copy of the map from the diffuse channel into the bump channel (output amunt 1; colormap disabled) and set the bump strength to about 30
time for a new testrender
2.2.5 Making the Sidewall texture
before we start to texture the sidewall youīll have to make a sidewall texture which can be mapped planar onto the tire.
in order to get something like the above you can crop a slice from the texture and follow this tutorial to bend it into circle (just make sure the tiling is the same as the tiling factor used for the tread)
2.2.6 Sidewall material
go to the multi/sub-object material
drag (copy) the mat from the tread slot to the sidewall slot
access the sidewall material
access the different maps in the slots and replace the files with the sidewall texture files
set the map channel to 2
set the tiling to 1
keep all the other settings
and do another testrender
2.2.7 Sidewall Bump
finally we have to apply a sidewall bump map
access the bump map slot
click on the button reading "Bitmap" and select the "Mix" map in the map browser.
keep the old map as a sub map
assign the sidwall bump map to the empty slot
donīt forget to set it to the right mapping channel (for more control add a new uvw mapping modifier to the stack and set up a new mapping channel)
set the mix amount to about 50
now you have to raise the bumpstrenght to about 60 (and eventually invert your bumpmap)
CPU Q6600 @ 3GHz Memory 8GB HDD Sansung, Western Digital
Graphics Card AMD Monitor Setup 2x22inch Samsung OS Win7
try rapidshare or save it as a jpg and attach it right here.
one point that i noticed: the tiling is a bit hard. try to get rid of the repeating pattern.
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A one-of-a-kind tutorial... I bet that many users out there were just waiting for tutorial like this :buttrock:
Originally Posted by EquiNOX
