More on bump maps

When to use bump maps.

This was made with Maya and rendered with mental ray.

The stone walls have a heavy bump map.  The material was made with a tileable stone texture and the bump map was made from the same seamless texture.

The bed was sculpted with the Maya sculpting tool found in Modeling under Surfaces.  The bedspread material is made from a seamless cloth texture and the bump map for it was made from the same seamless texture.

The cement floor was made from a seamless cement texture and again, the same texture was used to make a bump map.

The sink/toilet combo and the metal bars were made with mental ray “paint” materials.  Since they are smooth and shiny, they are not bump mapped.

This images can be clicked on to blow them up.

Here are two variations:

More on bump maps

Bump maps on plaster, metal, stone, and mortar.

The image below was made in Maya and rendered with mental ray.  The plants inside the building were made with PlantFactory.

The blue and white plasters were made with two seamless plaster textures used as the color of two mental ray materials.  Each material has a bump map made from the plaster texture used for its color.

The roof of the structure was made with a gold steel seamless texture used as the color of a Blinn.  The reflectivity, eccentricity, and specular rolloff were cranked up to make the material shiny.  The same gold steel texture was used to give the roof a deeper sense of depth.

You can click on this image to blow it up:

Below is a close-up of the front of the structure.  Note the heavy use of bump maps in the stone and mortar on the top of the arches.  This is crucial to making them look realistic.  Again, you can click on this image to blow it up.

Bump maps in Maya & using Photoshop to layer a texture

Bump mapping and layered textures.

The back wall on in this scene is made with a Blinn, with a layered textured made in Photoshop used as its color.  A bump map was added to the Blinn.

The layered texture was made with a yellow paster seamless texture, with a added Darken layer consisting of a damaged plaster seamless texture.

Immediately below is the original yellow plaster texture, followed by the damaged plaster texture.

Below those are the final layered texture output by Photoshop, followed by the final texture’s bump map.

The bottle is a revolved NURBS surface with a mental ray glass material.

The desktop is a wood seamless texture with a bump map made from the same texture.

The original yellow paster, before layering.

The damaged paster texture used as the Darken layer.

The resulting layered texture used in the scene.

The bump map used to give the back wall its gritty look.  You can see how important a bump map is!

Toon

This was made with the “toon” setting on Maya.  Go to the Rendering main menu, then go to Toon.  The color setting is 2; i.e., only two colors are allowed on the body of the cow, thus creating the 2D appearance.  The lettering was done within Maya under the Create > Text tool.

 

Making an arch in Autodesk Maya with the Polygon Bridge tool

Let’s make a simple archway using polygon modeling and the Bridge Tool.


Polygon cubes – two of them. 
We start out by setting the Main Menu Selector in the upper left of the Maya interface to Polygons.  (This step is not shown.) Next, we create a polygon cube.


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Duplicating the cube.
Since we just created an object, we are already in object mode, but in case we’re not, we right click and using the Marking Menu, put us in Object mode.
With the cube selected, we select Edit > Duplicate.  Now we have two identical cubes.


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Positioning our two cubes.
Now, we use the four way view to separate our two cubes using the  Move tool. We don’t need to put them into any particular locations to create our archway.  But it’s always a good idea to position objects in a deliberate fashion, so that later when we are putting more objects into our scene, we don’t need to move objects arbitrarily in 3-space to get the scene configured the way we want it.  In this case, we’re keeping our two cubes equidistant from the z-axis and at an identical distance from the x axis.


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Setting up the Bridge Tool.
As it turns out, the Bridge Tool that we will use only works on pieces of a single object.  So, while still in Object mode, we shift-select the two cubes and select Mesh > Combine.
(If we need to, we go into object mode, as shown.)


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Increasing the height of the side pillars of the arch.
We have already placed our cubes so that they are at the same height in the x-z plane; this will make it easier to ensure that our arch will not be lopsided. We don’t want our archway to begin its sweep close to the ground, so while we still have the two cubes (which are now part of a single object) selected, we use the Scale tool to make them both taller.   We note that the two cubes still have the same height, so our archway will not be lopsided.


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Now, we click click and go into Face mode, because that is what the Bridge Tool is going to act on – two faces.


The Bridge Tool: making the archway.
Now, we right click and go into Face mode, because this is what the Bridge Tool is going to act on – two faces.


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With the top faces of the two cubes shift-selected, we select Edit Mesh > Bridge, and we click on the little box at the right side of the menu selection, so that we can adjust the tool’s settings.


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We set the number of divisions to 10.  We also choose Smooth Path.


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Then, we hit Bridge, and boom, we have an archway!


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An example arch.
Here’s a model with an arch made using this technique.  It was rendered with mental ray.

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Autodesk Sketchbook and the Wacom Bluetooth stylus.

I do 3D modeling and animation.  I do not draw.
But – I have been experimenting with the Wacom Bluetooth stylus on my iPad.


The iPad and similar Android devices (as well as the Microsoft Surface notebooks) do not have pressure sensitive screens.

So, if you want to have pressure sensitivity when you draw, you need to use a stylus that senses when you press down (as opposed to the screen sensing the pressure); the stylus then sends a Bluetooth signal to the iPad.

The drawing application (in my case Adobe Sketchbook) catches this signal and makes the line you are drawing fatter.  (Of course, the app must be compatible with the Wacom pressure sensing Bluetooth protocol.)


It works great, with zero lag time!


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Lights in Maya – with mental ray

In the video tutorials on 3DbyBuzz, we look at the basics of creating lights in Maya, using ray tracing, and manipulating shadows.  We also look at the rudiments of global illumination and final gathering.  And we look at depth map versus ray traced shadows. Here, we look at a few other aspects of lighting in Maya, in particular, with the mental ray renderer.

Ambient occlusion.Ambient occlusion is a (usually subtle) shadow effect, which involves preventing light from reaching small, detailed areas in a scene. Here is the closet scene we have used in several of the videos and previously in this blog:

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In the scene, the only light is an ambient light.

Here is the scene rendered with mental ray:

closet-rendered-2013-09-29-20-33.jpg

Here is a rendered closeup of the left knob:

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If we go to Window, and then Rendering Editors, and then choose Render View, can then set the renderer to mental ray, and then choose Options.  Under the Indirect Lighting tab, we can check Ambient Occlusion.

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Now we go to the Passes tab and click on the top icon with the little orange light on it – the icon is just above the red dot in the image immediately below.


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We then hit Create.
Now we go back to the Main window and check off the Use Local AO Settings and set the Maximum Distance to 6.


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Bump maps versus displacement maps in Maya.

In the video tutorials on 3DbyBuzz, we have looked at the tradeoff between painstakingly crafting detailed geometry versus using bump maps to simulate geometric detail. Here, we look at another alternative, displacement maps, and compare it to bump maps.

Bump Maps. As a reminder, a bump map does not change the geometry of an object.  Rather, the normals information in a texture is used to create the illusion of texture on a model. Here is a Blinn material with a checkerboard bumpmap applied to it:

 

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This was created by first creating a Blinn material in the Hypershade, then creating a checkerboard texture in the Hypershade.  Then, with the material selected, the texture was middle-mouse-button dragged to the Bump Mapping box in the attribute editor above.

Displacement maps.

Here is another Blinn material, but this time, instead of using a bump map, we are using a displacement map.  We don’t do this by selecting the material itself.  Rather, we go to the Hypershade and choose the Shading Groups tab (instead of the Materials tab).  Then we select the second Blinn. We then create another checkerboard texture and drag it to the Displacement Mat box in the attribute editor of the Blinn Shading node.

 

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To emphasize this distinction, the image below shows the various tabs in the Hypershade window.  Notice that the two Blinns are labeled blinn3 and blinn6, and Maya provides very different icons for the two of them.  The first icon gives us a hint that a bump map has been applied.  The second icon is more abstract and indicates that we are using a different technique, namely displacement mapping. Notice also that the Materials and the Shading Groups tabs are quite different.

 

 

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The resulting render.

Below are two versions of a polygon glass dish in the same rendering.  They are identical geometrically.  On the left, a bump map has been used to create the feeling of detailed geometry.  On the right, a displacement map has been used instead. And the attributes of how the texture has been projected onto the material are identical.  The only difference is that in one, the texture serves as a bump map, and in the other, it serves as a displacement map.

The bump map.

The bump map creates an illusion of texture, but does not give us internal shadows or the sorts of light refractions that true, geometrically thick and detailed glass would.

The displacement map.

The displacement map, on the other hand, does much better.  However, it too, is only a simulation, although one that demands more computational time.  The geometry of the glass dish has not been changed; rather, at the point of rendering, Maya has substituted a 3D representation of the model, thus providing a true 3D rendering. Notice the depth of detail on the dish on the right.  The top of the dish gives a mottled look to the checkerboard that is reflected back to the viewer, while the one on the left simply bends the lines in the checkerboard. And the base of the right dish looks like true geometry, while the one on the left looks like there are simply dark lines drawn across the glass.  We’re getting the kinds of internal shadows (shadows being cast by a model onto itself) we expect with true geometry.

In sum.

All in all, the displacement map gives us a much richer sense of thick, cut glass. You can left click on the image below to blow it up:

 

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