Tidier way to apply these decals? Blended cubr projection maker

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  06 June 2013
I see... It is the effect as using a second mapping channel... But it is more efficient, since you don't have to store the UV coords again for the areas you want to have a different map.

Looks useful for when you need a small area to have a higher res map. It won't help you lay a decal over another map, though, right? Since each vertex can only have one set of UVW coords in a single mapping channel. You also then have to make sure your edges of your islands (elements) match in color as well.

I certainly understand the memory issue, especially on crazy hi-res meshes (I was doing the same kind of memory saving tricks with Magma Modifier to adjust maps for a Frost mesh created fro RealFlow particles.)

How much slower do two texture render? I sure would hope the difference would be negligible. It is in most renderers.
  06 June 2013
I got it now, thanks to PelDaddy and PiXeL_MoNKeY. I think mentally I was missing the connection between Offseting the actual maps themselves and turning off tiling, and the UVW Xform modifier. So this is indeed more efficient than using a new map channel.
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  06 June 2013
I get 46 vs 47 seconds render with one UVW map or two like I describe above (VRay ~2.5million poly sphere, fixed sampling cranked up).

I added two more (for four total UVW maps with different mapping channels and four textures into a composite map, each with a different mapping channel)... 50 seconds... again a 2.5 million poly object.

Once you add all the other effects renderers do these day I don't think multiple maps plays a huge role in slowing down renders. Rendering bitmaps is usually really, really fast (hence their use in games). Procedurals definitely slow things down the more you add, but it is other effects (glossy, refraction, GI, etc.), and fine details requiring more AA that really slow stuff down.

That trick is good to save memory, and very good when a small area needs a higher res map... Though another map with its own UVs on top would do the same thing and be a little easier to see and set up. Don't get me wrong; I am all for efficiency whenever practical...

There's an old saying in computer science.. Make it work... then make it fast. I would make the scene/object work (look right) first, in the easiest to set up manner. Then if the scene renders slowly I would look at what is slowing it down and fix that (like a programmer profiling their code).

Last edited by PelDaddy : 06 June 2013 at 07:12 PM.
  06 June 2013
So time will tell how efficient this works out for me - as Eric says, this will use more memory. I'll do a proper test later but for now, deleting duplicate shaders was more beneficial to me and procedurals are the render consumer at the moment.

So now my object IDs are free'd up to handle swapping colours, which mean duplicate material IDs were deleted, leaving material IDs to just swap shaders (I thought about using this method for displacement maps but that could prove dangerous so created a duplicate shaderas blurutility won't pipe through a Vrayblend material).

I'll explain based on my setup incase material or object Ids aren't doing it for you. And I'm open to suggestions on improvements if I'm missing a trick somewhere.

I highlighted on this image some of the variables for which maps need to be on/off for some of the objects (I've not marked all objects). Note: Top map is on for everything except the one object shown (the cab is also separate):

So Top map is set up in the regular way (no offset in the bitmap), then I've added a UVW xform mod to the geometry with the "No Top" arrow and offset it by one unit (in U) in the modifier which hides the bitmap from this one object utilizing empty UV space.

For the other maps, they are all offset by one unit (U) in the bitmap editor which hides them from all objects.

So I create a UVWxform modifier for each Left, R F B etc map. Offset the modifier by one unit (which reveals the corresponding bitmap) and then paste instance whichever modifiers are required on each object as per the image.

EDIT - And one important point - I was already past the point of no return for this part of my model. I.e. maps painted.

The cameramapgemini variation that is on Neil's site (I posted the link earlier) looks much better. You can simply turn projections on/off per object. It also works with the UVW xform modifier incase it's required.

I'll be using this method for the boom.

Last edited by MisterS : 06 June 2013 at 10:12 PM.
  06 June 2013
There is no right or wrong as long as it works for your specific needs. As always we all have our own different workflows, needs, and requirements. I am glad all of our input lead to something that does what you need.

"The Evil Monkey hiding in your closet."
  06 June 2013
Yeah thanks to everyone who helped me out - people on cgtalk have taught me a lot! Big respect.
  06 June 2013
Glad things are working out for you. The model and textures look really nice so far. I love what looks like the slight denting to the top of the cab (or is that just a reflection?) I also love the dirt at the base of the cab.

Sounds like you were already using a VRay Blend... Just to note the traditional blend and, especially the traditional Composite material are very slow with VRay. VRayBlendMtl is the way to go... And you can work around the lack of fog color support (if you need it for transparent objects) with a little creativity to get the fog color into the base layer.
  06 June 2013
Also, if you are looking for an easy way to render with and without certain textures have you considered just making two different versions of your bitmap (one pure black with zero alpha to make it disappear)? Sure, it is a hint slower, but not much, and it makes it really easy to swap out the textures to render it one way or the other. (Either with the asset manager, or simply by having to folder with bitmaps and renaming them as needed.)

Oftentimes the most basic solution is the easiest. You could also XREF your model and save out different versions that way to import into some other scene.
  06 June 2013
Hey PelDaddy, thanks, it's coming along - I'll hopefully look at texturing the boom next week using lessons learnt and I hope it will be a quick process. The roof is a combination of bump and reflection maps.

Regarding the black alpha versions - is that as a solution for hiding the image from certain objects or a quick means to enable/disable during the tweaking process? I've been using the standard composite map and enabling/disabling map trees as required. I've not had a good look at the vray comptex yet.

And re XREFS, This scene currently has three, but texturing has been done directly in each. But that's something I can improve on perhaps next project. Thanks again for your help.
  06 June 2013
I wasn't exactly sure what you meant when you said you would need to turn maps on and off. Is it just to see stuff, or is it to show your client both versions, or what?

What I meant was... Say you know you need to show or deliver two versions of your model, one with certain decals and one without. You could make a single version of the model and the materials, but then store your decals in a directory called decals. Then in another directory called decalsNOT you could have texture of the same name that are small 64 pixel blank images (blank alpha). So when you wanted to render one you could rename decalsNOT to decals and vice versa before you render. Not the easiest solution, since you can't queue them both on the farm in that case, but simple enough to do. You could also just change the paths in the Asset Manager in Max and save two versions of the scene.

You may be able to use scene states to save your textures versions. I have not used this extensively, but in light testing it works.
  06 June 2013
I just meant omitting the left decal on the right objects for example. If you see the original image, the left decals are shown on the right objects ie facing inwards which is incorrect. It's difficult to see in the last image that this has been fixed.
  09 September 2013
I just found an annoying problem with using UVW xforms to show/hide maps. Thought I'd post to save anyone else scratching their heads.

As mentioned previously the UVW Xform modifier is linked to the system scene units, rather than simply having an offset of 1 to offset 1 UV space unit for example. So if you have differing units between your hero object scene and your environment scene, and then you Xref one into another then your maps won't display.

You could go into your UVW Xform modifiers and set the offset to your parent system units but that's a really crap solution.

Anyone got a better method?

Fortunately all of my UVW Xforms were done in 4 separate scenes that share the same inch system units.

So I'll just Xref these and my environment (m) into a new scene using inches. Unfortunately luck isn't really a good solution.
  09 September 2013
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