Creation of Old, Dirty, Stained, Mossy Materials

[Bundie]

Hi

I am wondering what peoples work flows are for creating weathered materials?

I am doing an Arch Viz project and want to include an old weathered concrete corner of a building.

I know I can take a photo of a weathered wall and map it to my object, but I want to be precise and have control of the amount and location of the weathereing. for example a concrete wall with a downpipe were I can control the amount of water stains and moss growing around the pipe.
When I speak of control, I mean painting a certain amount of moss and water streaks (dirtyness in general) using Photoshop


Ive heard of texture baking and uvw unwrapping, but not sure what the best option would be.

Can someone point me in the right direction or possibly a tutorial that may help?

Thanks

[MrTom]

Tricky one.

There are really only two types of material...(at the very base level), procedural materials and Image based materials.

The first gives you the control you are looking for, but the second gives you a better end result. What you ultimately want is a procedural material that uses photographic Images (and Maps).

This is not impossible but will take some thought though. You'll have to really get your head around how to use procedural techniques to give you the area's of control you need, and then also on how to use Maps to give you the right effect in those area's.

It's not exactly difficult to do, but does require a good solid understanding of how materials are created....that and a lot of patience. I can't recommend any tutorials for you as (like everything else) there are just too many variations, but there should be enough 'material' tutorials out there for you to piece together enough info for this particular task......application of knowledge!!!!!

Procedural materials can give you an excellent result, and great control over the final look, but they can (and often do) get very involved to get them looking that good.

Image based materials give you a really good end result with very little effort.....the downside is lack of control....but, when it's so easy to change in PS it does become the preferred choice for most.

Mixing the two together is going to be the tricky part for you.

For the time being forget texture baking and UVW Unwrapping....you really need the material first before applying it to a mesh, as the material itself will influence what method of application will be most suited.

That's my 2¢ anyway.

Good luck.......you could be in for some long nights!

Regards.

[Bundie]

just what I need, more late nights

So just to get things straight in my head, would I use the Image based method to get my base concrete material (e.g. A&D Concrete Template) and somehow combined with the use of procedural materials to add the dirtyness? does that sound right?

[MrTom]

In a nutshell....yeah.

It just takes some forethought and forward planning as to what you want to be able to control and how to control it.

Split the material into different 'Passes' (for want of a better expression), and decide which 'Procedural' map will best suit each one. You'll have to use 'procedural' methods to get the control you want....once you have those sorted you can then use them to display the relevant parts of any 'Image' based maps you want to use.

Put another way, normally you would have a 'diffuse' map for the base......also a 'texture' map (or normal map) which can be used for things like 'bump' or 'displace'. You may also have another map for 'glossiness'.....and one for 'reflection'....in fact any parameter you want to have some control over. These would be greyscale images X pixels wide by Y pixels high.

The downside to using Image 'Maps' is that they need to be created in PS...ok, no big deal but if the end result isn't quite what you wanted then you have to edit the 'Map' for the offending parameter.........again, no big deal and often the easiest way to do things.

'Procedural' methods still use 'Maps' but they are mathematically created rather than by hand in PS.....the 'Maps' that come with Max like 'Noise', 'Tiles', 'Smoke'...etc are all 'procedural' maps...(the clue is they have a 'seed' value or 'phase' value to allow for animation.) These do create an 'Image' map as such but it can easily be changed by the use of spinners...all be it sometimes random.

The challenge you face is to re-create the greyscale 'Image' based maps (that you would normally create in PS), by using only the 'Procedural' maps already in Max. This is where the headache comes into it....with so many maps available and so many different parameters for each one it could take a while to get the right combination of 'maps' to give you the effect you need. Like I said it's not impossible but does take some time and a lot of planning and experimenting......and this will have to be done for EACH parameter of the final material that you want control over.

For example: You could have your 'Concrete' Image as a bitmap in the diffuse slot.
You could then put a 'Tile' map in the 'bump' slot.........
You could then put a 'Smoke' map in one of the map slots for the 'Tiles'......
You could then put a 'Noise' map in one of the map slots for the 'Smoke'.....
You may then want to do this for the other slots in both the 'Tiles' and the 'Smoke'.....

From this you can see that a simple material can very quickly become highly complex...but, it gives you total control over each aspect of the material. The above of course would also have to repeated for the other parameters of the Final Material that you wish to control....glossiness, reflect, displace...etc....which may (or more probably may not) use the same maps for the effect you want.....this is where the experimentation comes in! (And hence the late nights).

In your case getting 'Rusty water marks' using just procedural maps may be obtainable by using a 'smoke' map tiled many times one way and not the other....to give that 'stretched' look.....this may then need a 'noise' map too for any 'bump' or 'reflection' you need.....just where the 'water' part is. This 'Map' can then be used in the final material for masking the 'Rusty water'.....or whatever......which may still need another procedural map for masking as well.....who knows? LOL.

Sometimes you can get lucky and use the same map for controlling many different parameters.....a map to mask water could also be used for the reflection too as wherever you have water also needs to be reflective. This doesn't happen often though.

One thing to remember too......because 'procedural' maps work in 'world scale' you'll have to create a new material (even if it's the same one) for different sized objects. 'Procedural' maps have no 'size' like Image based maps and therefore will look different (in terms of scale) on different sized objects......this does of course totally rely on 'how' you plan to apply the material to the objects....you could get away with it with careful UVW mapping.....and thats another headache still to come!

Like I said, good luck.....it'll certainly keep you busy for a while, depending on how far you want to go with each 'procedure'.

I hope that clears that up a bit...not easy to explain...but then when it comes to Max what is? LOL.

Regards.

[Bundie]

thanks for in depth explanation, its making alot more sense to me now.

I gave it a quick try, and I can see the benefits of using the tile material, as it has some good controls.
Would have been usefull for a model I did not long ago with recessed on a concrete wall.

As for using the smoke to get dirtiness, well.......lets just say I understand what you mean by spending late night with trial and error.

So how would Wall-E from Pixar have been textured? using the procedural method explained or images maps?

[MrTom]

No worries, good to hear you're getting your head around it! Understanding the principles is the biggest hurdle to overcome.....once you understand how the thing works you can then concentrate on actually using it to your advantage....or sometimes not. LOL.

As to Wall -E, I dunno for sure.

A material created solely from procedural (mathematical) maps could be said to render quicker than one using Images....as the whole 3D thing is mathematically based anyway.........period. Image based materials, although mathematically created also (because they are digital images), tend to need more processing because the image file needs converting into something that the renderer can understand....first....and then it needs processing into the actual material.

I have seen, once, a material for VRay based on a certain Bavarian Motor Works company logo......purely made up of procedural maps.....now the logo itself isn't particularly complex but to replicate it in just procedural maps meant the material was fantastically over-complex. It looked good though I have to say, but was it worth the effort when 1 image in the diffuse slot could have done just as good a job, (if not better?).

It's a mystery to me as to why this method was used, I mean it's not as if you need any control over it....it's a badge that stays constant...so...?????? I dunno!

As for the Tile-thing....did you know that the 'Tile' map is just two 'Gradient Ramp' maps? (Set at 90° to each other). The control comes from moving the 'Grout' colour along the ramp, and changing it's width.....check it out and see if you can replicate it yourself.....like you've nothing better to do..... I know!

Keep at it, if you want to be able to control, at this level, all the parameters involved you'd better put your social life on hold for a month....or two.

(Alternatively just use an Image and go grab a beer with your mates!)

Regards.

[MrTom]

I have seen, once, a material for VRay based on a certain Bavarian Motor Works company logo......

....and here it is. Its a VRay material but the principle of using procedural maps is exactly the same.

The Material:





And what it looks like:




See what I mean? LOL.

Regards.

[Bundie]

dammn........now thats what you call a head ache....hahaha

amazing setup though. my hat goes off to whoever created it


I think im going to stick to an Image based material setups for this project, and research procedural materials as I go.

So my goal is to add mould and age on the wall just above the water level.
How should I approach this? do I render out the final image then in photoshop paint the mould? which would cause problems in the reflections

How do I approach this in the material?
My thoughts would be to unwrap the stone material, paint it in PS then re apply it and render again. Could this be the case?

[MrTom]

LOL....a wise move!

My thoughts would be to unwrap the stone material, paint it in PS then re apply it and render again. Could this be the case?

Yes in theory. You have to ask yourself does the wall NEED to be unwrapped? I don't know how you've constructed your 'wall' but if it's just flat (ok with some texture of sorts) then why go through the hassle of unwrapping?

If your 'wall' is either flat or 'box' shaped then why not just add the appropriate UVW map to the stack and be done with it? Unwrapping is normally reserved for the more 'organic' shaped mesh....basically when none of the standard mapping methods will work.

When all said and done a map is still just a flat image whatever, so you need to decide how best to put a 'flat' image onto your mesh. If it's a wall then I would assume it's flat (as far as the geometry goes) and therefore a single 'Planar' map would be more than enough. If the wall goes round a corner then 'Box' mapping would be better. Only if your wall looks like a dogs dinner would I suggest unwrapping it......and remember, even when unwrapped you will still be applying a 'flat' image to the mesh, it can't be anything but flat coz it's 2 dimensional!

So....with that in mind...yes. Create your image in PS with as much detail, (resolution) as you think you need. Apply this to the Diffuse slot of a material and apply it to the mesh.......add a UVW MAP (NOT Unwrap) modifier to the stack and click 'FIT'.......the default is a 'Planar' map so this is where you'll have to take over and experiment with the different maps...planar,box,cylindrical,spherical....etc.... ..my guess would be either planar or box. If the mapping needs to be moved then expand the modifier and select the gizmo.....this can be MR+S just like any other object.....adjust it till it fits where you want it....don't forget to turn on 'Show Map In Viewport' in the mat editor.

Once happy you can move onto the mould etc. You could do this on the same image used for the wall but a better way would be to do a completely differnrent image......you may even have a photo of real mould?

Whatever you use, also create another image but this time just black and white......have the black parts where you want the mould and the white parts where you don't. It doesn't really matter at this point if you swap these round....the map can always be inverted in the mat editor.

Now, if you combine these three images...ie with a 'Composite' or 'Blend' material you can have the wall image as the 'Base' layer....the Mould image as the covering layer and the B+W image as a mask for the mould......which type of material you use is up to you but you should find one that allows you to use two different materials 'mixed' together by a third map...the B+W one.

Now, when you have your material set-up and applied to the mesh the 'mould' part may not be where you need it.....this is the clever bit! The UVW Map modifier you added will have a 'Channel' number.....this relates to ANY map you use in the material. Channel numbers always default to 1 so at the moment EVERY map in the material is being placed by this single UVW Map.

To overcome this we can simply add another UVW Map to the stack but change the channel number to 2. It's a good idea to re-name these UVW Maps too so you know which one is controlling which image in the material!

As we now have another Map to play with we can assign the 'Mould' image (AND the MASK image) to this new channel....namely number 2.....in the Mat Editor.

This will then allow you to MRS the 'mould' all by it's lonesome....cute.

Thats the basics of it anyway. It would take me days to write out every single thing to do but with the above in mind and what I've said before you should be able to apply an image to your wall mesh which comprises of two images....the base and the cover layer. The 'amount' of 'mould' you see is controlled by the third image....remember this can be 'inverted' if it's arse about face.

So your final material will be a 'Composite' or 'Blend' or whatever you deem right, with one image for the 'Wall' and one image for the 'Mould'. The 'Mould' image could be a 'mask' map with the 'mould' image as the bitmap and the mask image as the mask. You will have two (2) UVW Map modifiers in the stack of the wall mesh....one to control the 'Wall' image (If it needs it that is) and one to control the 'Mould' image...with its mask.

It sounds more complex than it actually is and without knowing the scene and your construction methods it's impossible to say if ANY of the above is going to work for you......be prepared for it not to.

Anyway, see how you get on and just shout if you get stuck anywhere....it can be a complete bitch!

Good luck.

Regards.

[Bundie]

Fantastic Fantastic Fantastic,

Thankyou so much, that's making alot more sence in my head and I have a good grounding of where to start.

I will let you know how I go and post some images of my progress, so everyone can have a laught

Thankyou Sooooooooooo much for all your help so far