[ Texturing ] Windshield wiper trace effect

rares

Hi guys ! i'm trying to replicate the trace that a windhsiled wiper would create when passing over a dusty windshield, like you see in the photo below :



Does anybody have any tips on how to achieve this ? ( i'm using photoshop to create the texture )

MoP

Need more info, since there are many ways you could do this, depending on what engine/renderer/shaders you're using.

Are you allowed alpha blended textures? If so, that seems the obvious way to me - diffuse texture with dirty parts and clean parts as shown in the photo, then an opacity map where the dirty parts are more opaque and the cleaner parts are more transparent.
You could also use this same alpha value for controlling how reflective the windscreen is - again though, this depends on what shaders and textures you're allowed.

rares

no transparency required here, it will be a matte color texture, imagine that my PS layers are like this:

- dust layer
- glass color layer

the windshield wiper pattern will go in the mask of the dust layer, all i need to know is how would i create that pattern ( i've tried creating the semi circles the wiper would describe and cutting out the bits that shouldn't be there, but there must be an easier way)

pyromania

Use the rectangle tool, make sure it set to paths. Drag out a rectangle roughly the size of one of the wiper arcs. Use the add anchor point tool to add new mid-points to the two horizontal sides of the rectangle ( just eye the midpoint ). Then take the direct select tool, select the two anchor points you just created and drag them up. You should now have two nice arcs on the top and bottom. Tweak the shape of the path however you need then turn it into a selection for you layer mask.

MoP

Heh, I'd just paint it probably. I thought you were after something more specific :P

rares

thanks for the help guys