Blender 2.5: Simulating Manufactured Materials

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Blender 2.5 Materials and Textures Cookbook

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Over 80 great recipes to create life-like Blender objects

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by Colin Litster | April 2011 | Open Source Web Graphics & Video

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The Blender 3D suite is probably one of the most used 3D creation and animation tools currently in existence. The reason for that popularity is both its tool set and the extraordinary fact that it can be downloaded free of charge.

In this article by Colin Litster, author of Blender 2.5 Materials and Textures Cookbook, we will cover:

  • Creating metals
  • Using specular maps to add age and variety to man-made surface materials
  • Adding oxidization weathering to our copper material
  • Adding grime and artistic interest to our copper material

 

Blender 2.5 Materials and Textures Cookbook

Blender 2.5 Materials and Textures Cookbook

Over 80 great recipes to create life-like Blender objects

        Read more about this book      

(For more resources on Blender, see here.)

Creating metals

Of all material surfaces, metals must be one of the most popular to appear in 3D design projects. Metals tend to be visually pleasing with brightly colored surfaces that will gleam when polished. They also exhibit fascinating surface detail due to oxidization and age-related weathering. Being malleable, these surfaces will dent and scratch to display their human interaction. All these issues mean that man-made metal objects are great objects to design outstanding material and texture surfaces within Blender.

It is possible in Blender to design metal surfaces using quite simple material setups. Although it may seem logical to create complex node-based solutions to capture all the complexity apparent within a metal surface, the standard Blender material arrangement can achieve all that is necessary to represent almost any metal.

Metals have their own set of unique criteria that need application within a material simulation. These include:

  • Wide specularity due to the nature of metals being polished or dulled by interaction
  • Unique bump maps, either representing the construction, and/ or as a result of interaction
  • Reflection – metals, more than many other surfaces, can display reflection. Normally, this can be simulated by careful use of the specular settings in simulation but, occasionally, we will need to have other objects and environments reflected in a metal surface.

Blender has a vast array of tools to help you simulate almost any metal surface. Some of these mimic real world metal tooling effects like anisotropic blend types to simulate brushed metal surfaces, or blurred reflections sometimes seen on sandblasted metal surfaces. All these techniques, while producing realistic metal effects, tend to be very render intensive. We will work with some of the simpler tools in Blender to not only produce realistic results but also conserve memory usage and render times.

We will start with a simple but pleasing copper surface. Copper has the unique ability to be used in everything from building materials, through cooking, to money. Keeping up with a building theme, we will create a copper turret material of the type of large copper usage that might be seen on anything from a fairy castle to a modern day embellishment of a corporate building.

One of the pleasant features of such a large structural use of copper is its surface color. A brown/orange predominant color, when new, is changed to a complementary color, light green/blue, when oxidized. This oxidization also varies the specularity of its surface and in combination with its man-made construction, using plating, creates a very pleasing material.

Getting ready

To prepare for this recipe, you will need to create a simple mesh to represent a copper-plated turret-like roof. You can be as extravagant as you wish in designing an interesting shape. Give the mesh a few curves, and variations in scale, so that you can see how the textures deform to the shape. The overall scale of this should be about 2.5 times larger than the default cube and about 1.5 times in width at its widest point.

If you would prefer to use the same mesh as used in the recipe, you can download it as a pre-created blendfile from the Packtpub website.

Blender 2.5: Simulating Manufactured Materials

If you create a turret-like object yourself, ensure that all the normals are facing outwards. You can do this by selecting all of the vertices in edit mode, and then clicking on Normals/ Recalculate in the Tools Shelf. Also, set the surface shading to Smooth in the same menu.

Depending on how many vertices you use to create your mesh, you may want to add a Sub-surface modifier to ensure that the model renders to give a nice smooth surface on which we will create the copper-plating material simulation.

In the scene used in the example blendfile, three lights have been used.

A Sun type lamp at location X 7.321, Y 1.409, Z 11.352 with a color of white and Energy of 1.00. However, it should only be set to provide specular lighting. It is positioned to create a nice specular reflection of the curved part of the turret.

A Point lamp type set at X 9.286, Y -3.631, Z 5.904 with a color of white and Energy of 1.00.

A Hemi type lamp at location X -9.208, Y 6.059, Z 5.904 with a color of R 1.00, B 0.97, B 0.66 and an Energy of 1.00.

These will help simulate daylight and a nice specular reflection as you might see on a bright day.

Now would be a good time to save your work. If you have downloaded the pre-created blendfile, or produced one yourself, save it with an incremented filename as copperturret- 01.blend.

It will also be necessary for you to download, three images that will provide a color map, a bump map, and a specular map for the plated surface of our turret. They are simple grayscale images that are relatively easily created in a paint package. Essentially, one image is a tiled collection of metal plates with some surface detail, and the other is derived from this image by creating a higher contrast image from the first. This will be used as a specularity map. The third has the same outline as each tile edge but with simple blends from black to white. This will provide a bump map to give the general slope of each metal plate. All three, separate, are available for download from Packtpub website as:

  • Chapt-02/textures/plating.png
  • Chapt-02/textures/plating-bump-1.png
  • Chapt-02/textures/plating-spec-pos.png

Once downloaded, save these files into a textures subdirectory below where you have saved the blendfile.

Blender 2.5: Simulating Manufactured Materials

How to do it...

We are going to create the effect of plating on the turret object, tiling an image around its surface to make it look as though it has been fashioned by master copper smiths decades ago.

  1. Open the copper-turret-01.blend. This file currently has no materials or textures associated with it. With your turret mesh selected, create a new material in the Materials panel. Name your new material copper-roof.
  2. Change the Diffuse color to R 1.00, G 0.50, B 0.21. You can use the default diffuse shading type as Lambert.
  3. Set the Specular color to R 1.00, G 0.93, B 0.78 and the type to Wardiso with Intensity 0.534, and Slope 0.300.

That's the general color set for our material, we now need to create some textures to add the magic.

  1. Move over to the Texture panel and select the first texture slot. Create a new texture of type Image or Movie, and name it color-map.
  2. From the Image tab, Open the image plating.png that should be in the textures subfolder where you saved the blendfile.

This is a grayscale image composed from a number of photographs with grime maps applied within a paint package. Each plate has been scaled and repositioned to produce a random-looking, but tileable texture. Creating such textures is not a quick process. However, the time spent in producing a good image will make your materials look so much better.

  1. Under the Mapping tab, select Coordinates of type Generated Projection and of type Tube.
  2. Under Image Mapping, select Extension/ Repeat, and set the Repeat values of X 3 and Y 2.
  3. This will repeat the texture three times around the circumference of the turret and two times on its height.
  4. In the Influence tab, select Diffuse/Color and set to 0.500. Also, set Geometry/ Normal to 5.00. Finally, select Blend type Multiply, RGB to Intensity, and set the color to a nice bright orange with R 0.94, G 0.56, and B 0.00.

Save your work as copper-turret-02.blend, and perform a test render. If necessary, you can perform a partial render of just one area of your camera view by using the SHIFT+B shortcut and dragging the border around just an area of the camera view. An orange-dashed border will show what area of the image will be rendered. If you also set the Crop selector in the Render panel under Dimensions, it will only render that bordered area and not the black un-rendered portion.

Blender 2.5: Simulating Manufactured Materials

You should see that both the color and bump have produced a subtle change in appearance of the copper turret simulation. However, the bump map is all rather even with each plate looking as though they are all the same thickness rather than one laid on top of another. Time to employ another bump map to create that overlapped look.

  1. With the turret object selected, move to the Texture panel and in the next free texture slot, create a new texture of type Image or Movie, and name it plate-bumps.
  2. In the Image tab, open the image plating-bump-1.png.
  3. Under the Image Mapping tab, select Extension of type Repeat and set the Repeat to X 3, Y 2.
  4. In the Mapping tab, ensure the Coordinates are set to Generated and the Projection to Tube.
  5. Finally, under the Influence tab, only have the Geometry/Normal set with a value of 10.000.

Save your work, naming the file copper-turret-03.blend, and perform another test render. Renders of this model will be quite quick, so don't be afraid to regularly render to examine your progress.

Blender 2.5: Simulating Manufactured Materials

Your work should have a more pleasing sloped tiled copper look. However, the surface is still a little dull. Let us add some weather beaten damage to help bind the images tiled on the surface to the structure below.

  1. With the turret object selected, choose the next free texture slot in the Texture panel. Create a new texture of Type Clouds and name it beaten-bumps.
  2. In the Clouds tab, set Grayscale and Noise/Hard, and set the Basis to Blender Original with Size 0.11, and Depth 6.
  3. Under the Mapping tab, set the Coordinates to Generated, and Projection to Tube. Below projection, change the X,Y,Z to Z, Y, X.

    Blender 2.5: Simulating Manufactured Materials

  4. Finally, under the Influence tab only, select Geometry/Normal and set to -0.200.

Save your work again, incrementing the filename to copper-turret-04.blend. A test render at this point will not produce an enormous difference from the previous render but the effect is there. If you examine each stage render of the recipe so far you will see the subtle but important changes the textures have made.

Blender 2.5: Simulating Manufactured Materials

How it works...

Creating metal surfaces, in 3D packages like Blender, will almost always require a photographic image to map the man-made nature of the material. Images can add color, bump, or normal maps, as well as specular variety to show these man-made structures. Because metals can have so much variety in their surface appearance, more than one map will be required. In our example, we used three images that were created in a paint package. They have been designed to give a tileable texture so that the effect can be repeated across the surface without producing discernible repeats.

Producing such images can be time consuming but producing a good image map will make your materials much more believable. Occasionally, it will be possible to combine color, bump, and specularity maps into a single image but try to avoid this as it will undoubtedly lead to unnatural-looking metals.

Sometimes, the simplest of bump maps can make all the difference to a material. In the middle image shown previously, we see a series of simple blends marking the high and low points of overlapping copper plates. It's working in a very similar way to the recipe on slate roof tiles. However, it is also being used in conjunction with the plating image that supplies the color and just a little bump.

We have also supplied a third bump map using a procedural texture, Clouds. Procedurals have the effect of creating random variation across a surface, so here it is used to help tie together and break any repeats formed by the tiled images.

Using multiple bump maps is an extremely efficient way of adding subtle detail to any material and here, you can almost see the builders of this turret leaning against it to hammer down the rivets.

Blender 2.5 Materials and Textures Cookbook Over 80 great recipes to create life-like Blender objects
Published: January 2011
eBook Price: $26.99
Book Price: $44.99
See more
Select your format and quantity:
        Read more about this book      

(For more resources on Blender, see here.)

Using specular maps to add age and variety to man-made surface materials

To help add that copper shine seen in newly installed copper roofing, we will add a specular map to increase the specular reflection but varying it to simulate what happens to copper when exposed to air for only a few days.

Getting ready

If you completed the previous recipe, load the copper-turret-04.blend saved earlier. Alternatively, you can download a pre-created blendfile from the Packtpub website.

How to do it...

We will now add a specular map to our copper material simulation. So, Open the copper-turret-04.blend, and select the turret object.

  1. From the Texture panel, select the next free texture slot. Create a new texture of type Image or Movie and give it the name specular-bump.
  2. In the Image tab, Open the file plating-spec-pos.png.
  3. Under the Image Mapping tab, select Extension of type Repeat and set the Repeat to X 3, Y 2.
  4. In the Mapping tab, ensure the Coordinates are set to Generated and the Projection to Tube.
  5. Finally, under the Influence tab, only select Specular/Intensity and set to 1.000, and Hardness and set to 0.500.

Save your work once again, incrementing the filename to copper-turret-05.blend. Render a full-size image to see what our nearly new copper turret roof looks like.

Blender 2.5: Simulating Manufactured Materials

How it works...

When you are using images and procedurals, without UV mapping, you need to map them onto the surface of your mesh using one of the projection methods. Choosing which one can sometimes be tricky but a good rule of thumb is to look at your mesh and consider it as a simplified shape. So, in our case, the turret is not a cube or sphere, and it's certainly not flat. So, the nearest to its shape would be a tube.

Of course, you will inevitably get some distortion if your mesh is complex but providing it appears to work, it should be OK. In our case, the top of the mesh is narrower than the base so the tube projection will get smaller further up the model. However, that doesn't really matter as the plating would need to be smaller on these tricky to plate areas anyway.

We have also used an image to control both the intensity and hardness of the specular shine of the surface. Image maps are ideal for this purpose and can add an enormous amount of detail when light catches these changes in the specular effect provided by a simple grayscale image. It can be particularly effective if the light source or object move in an animation.

There's more...

The plating-spec-pos.png image is a positive higher contrast copy of the plating.png file. Just by playing with the levels command within your paint program, you should be able to extract portions of your image that could be used as a specular mask. The reason why I called this positive was because at the time I wasn't sure if I needed a positive or negative version of the image to create the specular variation I wanted. It was easier therefore to create two images by simply inverting one and saving it with another name. In the end, I didn't need the negative image but wanted to raise the issue here as it's very easy to produce positive or negative images for use as specular or bump maps in any paint package.

It is also possible to place lights to give interesting specular highlight to help frame the object. You can actually turn off the Diffuse setting of such a special light so that it will not light the whole of the object but just its specular areas. You are then free to move that light to give the best specular reflection. In this example, the lights suggested in the earlier recipe Creating metals, were positioned to give good specular highlights to show the variation across the plated copper surface.

Adding oxidization weathering to our copper material

Copper doesn't stay that pristine for very long. Oxidization will soon turn its surface green. Often, this will happen in varying amounts across the surface because of material differences between plates and because of damage to any protective coating, as well as natural variations in weathering. All these things can help add artistic interest to a copper material, so let's see how to add some copper weathering to our material simulation.

Getting ready

Reload the copper-turret-05.blend created at the end of the previous recipe or download a pre-created file from the Packtpub website.

How to do it...

We can start by applying a green color that blends with the copper color to give more oxidization on the top half of the turret. We can use the Blender procedural texture Blend to achieve this.

  1. With the turret object selected, and the Texture panel active, select the next free texture slot and create a new texture of type Blend. You should name this Blend.
  2. In the Blend tab, make the Progression Linear, and the direction Horizontal.
  3. Under the Mapping tab, select Coordinates Generated, and Projection Flat. Just below this, set the X,Y, Z settings to Z, None, None.
  4. Under the Influence tab, set Diffuse/Color to 1.00 and set the Blend type to Mix, and set RGB to Intensity with a color setting of R 0.51, G 0.73, and B 0.38.

Always save your work after each stage of these recipes, incrementing the filename at each save. If you render at this stage, you will see a gradual change of color from our copper orange at the base of the turret through to a dull green at the top. However, metal weathering is never this even. Let us add another texture to produce some random variation to the green oxidization.

  1. With the turret selected, move to the Texture panel and select the next free slot. Create a new texture of type Image or Movie and name it oxidization.
  2. In the Image tab, Open the image plating-spec-pos.png.
  3. In the Mapping tab, ensure the Coordinates are set to Generated and the Projection to Tube.
  4. Under the Image Mapping tab, select Extension of type Repeat and set the Repeat to X 3, Y 2.
  5. In the Influence tab, select Diffuse/Color with a value of 1.000. Set the Blend type to Mix, check Negative and Stencil, as well as RGB to Intensity with a color of R 0.51, G 0.73, B 0.38.

Save your work, once again incrementing the filename to copper-turret-06.blend, and perform a test render of the full height of the turret. You should see that the green oxidization varies across the surface giving a quite realistic oxidized copper turret.

Blender 2.5: Simulating Manufactured Materials

How it works...

In this recipe, we changed the mapping of the blend texture by remapping its coordinates to other axes and also to remove it from certain axes. We are able to remap any texture, image, or procedural onto other co-ordinates by employing the Mapping tab coordinate controllers. This is useful if you want a texture to appear on the sides of a model rather than the top. Of course, we can also set Cube mapping that will essentially copy the same image to each face of a theoretical cube. But, what if we would prefer to map the flat image to one side, rather than all round, or just the top? We can use the three controllers in the Mapping tab to remap the X Y Z coordinates to other surfaces. The following image illustrates what is required to map to the top (Z direction), the left side (X direction), or the right side (Y direction). Apart from remapping to other axes, we are also able to turn off any of the axes projections by selecting None. You may have to alter more than one of the remap co-ordinates to ensure the texture is not reversed.

Blender 2.5: Simulating Manufactured Materials

The blend procedural is not a flat texture. It exists metaphorically in 3D space, so if it's applied to a cube that you are viewing from inside, the blend will occur across the entire internal space of that cube. Its direction, however, is controlled by its blend and mapping settings.

What we have done here is remap the normal X direction to the Z axis, which is basically up and down. We have turned off the other directions as they are not needed. That means we can employ the blend texture in all directions, which is useful in our example as we wished to add the oxidization from the top of the turret.

We also employed the specular map a second time. Here, it is used to paint the green oxidization onto only those black areas of the image. These are the parts that produce the least specular highlight as specified in the earlier specular-bump texture. The previous blend texture acts as a mask because of its stencil setting, which means that the green oxidization merges with the blend green, producing a more random distribution of the oxidization effect.

We have also applied the stencil for this repeated image texture so that both it and the blend will mask the following texture. Masks are always valuable and you don't need a node material to produce quick dramatic results. Here, it will be used to vary a following dirt type texture in the following recipe.

Adding grime and artistic interest to our copper material

The cooper turret created in the previous recipes may be accurate in terms of color, and aging of real copper, but sometimes it's useful to go beyond reality and add other textures to dirty a material simulation just because it looks better. We can do this with our simulation by adding two further textures.

Getting ready

This recipe uses the blendfile saved at the end of the last recipe. If you have not completed that recipe, you can download the following file from the Packtpub website: cooperturret- 06.blend.

How to do it...

We will begin by adding a repeated texture to mix a lighter green color to the areas of the turret not masked by the blend but controlled by the specularity image map.

  1. With the turret object selected and from the Texture panel, select the next free texture slot and create a new texture of type Clouds. Name the texture dirt-streaks.
  2. In the Clouds tab, select Grayscale, and Noise/Soft. Select Basis type Blender Original with Size 0.15 and Depth 6.
  3. Under Mapping, select Coordinates type Generated and Projection type Tube. Change the Size Z value to 0.50.
  4. Under Influence, set Diffuse/Color with a value of 1.000. Set the Blend type to Multiply and the color selector to R 0.96, G 1.00, B 0.96.

Save your work one last time as cooper-turret-07.blend and perform a render.

Blender 2.5: Simulating Manufactured Materials

A copper turret material that can be applied to any shape tower you desire.

How it works...

The final dirt-streaks, is a simple Clouds texture with its Z size reset to 0.50. This will essentially stretch the texture in the up and down direction to imitate dirt washed by rain, etc. It will also only form on those areas of the material not masked by the stencil command of previous textures. So, here it is masked by both the specular-bump, and blend textures to some degree or other. The result is random dirt that appears to collect mostly on those areas affected by oxidization.

Simple use of the stencil command can produce some quite dramatic results.

Summary

In this article we took a look at ways to simulate manufactured materials.


Further resources on this subject:


Blender 2.5 Materials and Textures Cookbook Over 80 great recipes to create life-like Blender objects
Published: January 2011
eBook Price: $26.99
Book Price: $44.99
See more
Select your format and quantity:

About the Author :


Colin Litster

Colin is well known in the Blender community for his series of well received tutorials on material and texture creation in Blender. He has extensive knowledge of special effects creation following his early career in the film industry. Colin subsequently went into Higher Education rising to the level of Head of IT and Media Production at a leading UK University.

Colin runs a well known Blender Blog called Cogfilms.com in which he has promoted the development of Blender encouraging users to attempt the impossible in 3D creation.

Colin has been working on a feature film production over the last few years whose title is Cog which is also Colin's internet persona.

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