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Is there a way to make decals with vraybitmap? I put several of them together in a composite map with tiling turned off, and the top layer in the composite just covers the ones below with black in the area outside the map instead of revealing them and the base material. When I use the built-in max bitmap it works as expected. Am I just missing a checkbox somewhere? I would prefer to use vraybitmap for everything if I can since the mapping source feature is great. Thanks!
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Works as expected on my end. Could you attach a simple scene, in which the issue is present? Screencaps would be lovely as well. -
Hi Aleksandar. Thanks for the reply. Of course, when I tried to reproduce the issue, it worked fine. So I assume I just set up something incorrectly in my original file.Originally posted by hermit.crab View Post
I'm trying to tile 9 different USGS images on a large plane. In the file, I included two planes, one with material using standard bitmaps which works as expected, and one that uses vraybitmaps. In this file, I have all the maps plugged into a multi tile, but I got the same results when I plugged them into a composite map. I'm really not sure what I did differently here vs when I tried to reproduce the problem. When I was setting this up, I started from scratch several times thinking I might have fat-fingered a checkbox somewhere, but I got the same result every time. I can only assume it has something to do with the unwrap I'm using. I'm baffled. Let me know if you need any other info.
I've attached the max file and a test rendering. Here is a link to the maps: https://we.tl/t-qIxGthIA7W (they're the original huge textures because I couldn't reproduce the issue in a simpler file)
Thanks!
3ds Max 2021.3.2
vray 5, update 1.3
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I just tried it again with a planar uvw map that is 1/9 the size of the plane, which is how I should have mapped it from the beginning. But it didn't fix the problem, so it doesn't have anything to do with the unwrap.Comment
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Your VRayBitmaps' Alpha Sources have been set to opaque. This produces a black background (instead of transparency), which overlaps all other tiles. Set the Alpha Sources to "Image Alpha" to resolve it.
Also, there seems to be a difference in how Bitmaps and VRayBitmaps handle the Opaque function, which is from where the confusion stemmed.Comment
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Ahhh ok. The .tiff's I get from USGS have alpha channels included in them that I want vray to ignore though. Is there any way to do that without producing the black background? Or would I have to remove them from the image files first in photoshop or something?Originally posted by hermit.crab View PostComment
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Is there a reason to remove the .tiff's alpha channels, rather than simply apply them?Comment
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USGS uses the alpha channels in their images for some other gis/geographic data that is probably important for use in other applications, but they do affect how they render when used in the diffuse as-is. In the past, we have just used single images or stitched them together in photoshop and discarded the alpha channels in pshop or in the material so they would render correctly.Originally posted by hermit.crab View Post
Additionally, sometimes if we haven't chosen the correct setting in pshop when we export a .tiff texture, and it brings an alpha channel with it, a quick fix is to just turn off the alpha in the bitmap in max.
Not a huge deal ultimately, just curious. From a v-ray standpoint, is there any advantage to including a black background in the map when alpha is turned off? Trying to think of a situation in which that would be desirable.Comment
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There isn't a particular reason for it; most renderers handle it differently since there isn't a standard. Otherwise, contact us again if you run into trouble again.Comment
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