Carey House Tutorial 04 - Texturing

As promised, in this tutorial we are going to have a look at the texturing of the Carey House building itself.  There are several basic techniques involved with texturing a building such as this in our workflow which we use for almost all architectural projects involving a few scripts and modifiers which we will run through. 

The timber cladding is one of the main materials in this scene.  The basic geometry is split into several meshes corresponding to the constructional element so that each may be textured using different bitmaps and orientated seperately using UVW modifiers. i.e. Mesh 01 = long horizontal plate, mesh 02 = cross horizontal plate, mesh 03 = vertical fins, mesh 04 = vertical cladding.

Each mesh was then given a UVW Map which is rotated and scaled to fit a single element in the mesh.  Box mapping is usually best for this.

The timber material was made using a series of 21 bitmaps each approximately dimensioned to fit a full board.  We modified the bitmaps in photoshop depending on their position in the building to add some weathering effects.  In this instance the vertical cladding is protected at the top by a top plate overhanging 150mm resulting in differential weathering of the material.  The timber used is a type of fir which, unweathed, is fairly orange but weathers down to a silvery grey.  To create this effect we desaturated the timber bitmap in Photoshop leaving only a protected area at the top with increased saturation.  The transition was graded with a few overlays to produce a semi weathered effect.

CG Source's Multi Texture  Multi Texture plug in was used to create the material in 3ds max. The 21 premade timber textures were loaded into a Multitexture material and plugged into a standard vray material.  Colour Correction can be used to create maps for additional channels of required such as bump, reflection and reflection glossiness.  Highlight gloss was also used in this example to cheat an effect in a specific lighting set up but this is pretty old-school now and not something which we would typically use. Make sure the Multitexture material is set to Material ID and the blur value isn't too high.  0.2 seems to work well for most applications.  The great thing about Multitexture is the colour adjustments.  I usually mess around with the gamma settings to create subtle or sometimes not so subtle variations in the materials.  this pretty much guarantees that even with fewer than 21 bitmaps it is very unlikely that you will get any perceivable tilling or repetition in your texture.

Before assigning the material to the geometry, all the elements in the mesh (i.e. each timber board) must be given a unique material ID.  Again CG Source have an excellent free script called unique mateial ID which generates unique ID's for geometry.  If all your objects are attached as a single mesh as in this case, select the mesh and click Unique Mat ID's per object. 

The material can then be applied to the geometry which is already UVW mapped.  Sometimes a bit of reshuffling of the UVW map is necessary. 

Moving on to the glazing.  We use a slightly different technique to achieve a similar result.  The basic architectural glass material is fairly simple.  We tend to increase max depth in the reflection channel to 10 (5 is default). This is important if you are looking through several pieces of glass particularly if they are double glazed units and you also have reflect on back side checked meaning you get 4 reflections from each window. Sometimes this can be visually confusing having four reflections and unchecking reflect on backside can result in nicer double glazed reflection.

We also used a subtle very light green fog in this glass which is sometimes gives a nice effect in architectural glass. Be very warey of both the colour and multiplier however as refractive fog can have very strong and undesirable effects. 

We add two types of bump to the basic glazing to create imperfections in the glass and more realistic reflections, noise and edge falloff.  The noise provides a subtle wavy reflection to the glass whilst the edge falloff bitmap creates a buldge effect giving the impression of the two pains of glass having been clamped at the edges.  (In reality generally the lower quality the glass the greater the buldge and wavyness)

These are comped together using a VrayCompTex with the Operator set to Multiply.  The noise is procedural and the edge fall off or 'buldge' is a bitmap.  A UVW modifier is applied and set to face, this sets 'buldge' bitmap to fit the glassing elements and the noise can be adjusted independently in the size parameters of the map.  This is unit specific so be careful to check your unit setup.  400-500 seems to work well when working in cm. 

The final stage in basic architectural glazing is to prevent the noise map in the bump form crossing from one pane across to an immediately adjacent one.  There are two stages to this. Firstly the material must be copied several times (4 in this case) to enable randomisation.  The four glass materials can then be added to a Multi/SubObject with 4 ID's.  Make sure the phase of the noise is different in each glass material which has the effect of shifting the noise around.  

Secondly add a MaterialByElement modifer to the glass mesh, increase the ID count to 4 to match the Multi/SubObject and change the value to 25.0 for each which will provide an equal distribution of material ID's across elements in the mesh.  If it's not looking right, the seed value can be rolled up and down until you achieve the desired result.  A dummy material can be useful when adjusting the seed value for some real-time feedback.

A similar technique can be used for kitchen cupboard fronts to vary the bump. 

More ID's sometimes required to ensure randomisation

Another important aspect of architectural glazing is the frames.  I think detail in glazing frames is one of the key areas of detail in a model which can lift the whole scene.  Even if barely perceptible in the render it is always worth doing in my opinion.  In this case we used a pretty standard narrow site line double glazed triple track sliding system with silver spacer bars.

The material for the spacer is a simple brushed stainless steel with a bump map for the dimples UVW mapped onto it.

Free spacer bar bump map

As a round up, a material technique which we use on almost all materials is the VrayEdgesTex.  This is a type of bump procedure which simulates the sharp arrases having been rounded off the material.  As there is no displacement involved so it doesn't add render time and allows much of your geometry to have a much lower polycount on account of not having to round off the geometry with quad champher or round corners in Sketchup!  When using VrayEdgesTex in conjunction with other bump maps on a material a composite map can be used.  VrayEdgesTex seem to work best however with bump set to 30 in the maps rollup of the vray material.  If a lower value is required for any other procedural bump maps this is best adjusted in the Output Amount of the map.

(Incidentally for any of you using Corona Renderer this is a built in parameter in the render settings avoiding any comping. Very handy!)

Original material provided by the inimitable Bertrand Benoit 

We will continue with some final texturing of water and other elements in the courtyard in tutorial Number 5!