Inventor: A Teapot Tale

December 18th, 2012

Product or model presentation is one of the most important factors when submitting a project to a customer or the public. It permits you to accurately portray and describe the model, while making it look appealing at the same time.

In this article I will introduce you to the process of making an appealing image out of the part/assembly, using Autodesk Inventor®. I’ll also teach you the tricks I learned while using Autodesk® 3ds Max®.

Let’s begin with the Autodesk Inventor renderer (Inventor Studio) and the basics of its usage.  All the renderings will be explained using a simple, classic “teapot” part.

Inventor Studio

Global Lighting

To start, we will use Global Lighting, which is the easiest way to make your object look nice and smooth and a tiny bit realistic. This is the most common way of rendering an object.

To render an image using Global Lighting go to Inventor Studio; click Render, and choose Global Lighting as your lighting style. Hit Render and wait until a full image is rendered.
You should get something similar to Figure 1 image (I always use the Millennium color scheme; therefore, my background is blue.)

Figure 1

Global Lighting is a lighting style that spreads out evenly throughout the scene. The scene is lit directly from top, making the objects cast shadows vertically down.
But this is not what we want to see. The object still looks flat with poor display of its shape and definition.

Here is where the first trick comes in handy—the “ground.” Your object is now placed on a basic surface, letting the light and shadows bounce off it, highlighting the definition of the object, as well as making it look more “down-to-earth”; it is no longer floating in an endless space.  See Figure 2.

Figure 2

Figure 3 is a side-by-side comparison of the teapot floating in viewport, and placed on a surface. Note: the lighting style was not changed.

Figure 3

Local Lights

Unlike Global Lighting, a Local Light adds a more cozy feeling to your rendering. It is not evenly distributed light; rather, it concentrates on one spot, leaving everything else around it in darkness.

There are two types of Local Lighting—Omni Light (think of it as an uncovered light bulb) or a Spotlight (a more directional light).

For this example, I have arranged two Spotlights to aim at the teapot from two directions – front and back.

The settings for both of them are:

  1. Decay: None
  2. Hotspot: 5 degrees (the actual light)
  3. Falloff: 75 degrees

Don’t forget to turn on soft, high-quality shadows in the Shadows tab in the light properties window.  This setup indicates that my two lights are mostly “falloffs” of the spot light, which should produce very soft shadows and nice gradients both on the scene and on the object. See Figure 4.
 

Figure 4

In the window that pops up when you click Render Scene for this setup, you must choose High Quality Antialiasing in the Output tab, otherwise the render will have a lot of artifacts.
Figure 5 shows the result.

Figure 5

Looks nice, doesn’t it? But this setup will require quite a bit of your time to be rendered,  so be prepared.

Cameras

This bit is quite straightforward. Add a Camera to your scene, point it at the object, move it where you want it. The fun part is the ability to choose the Zoom Angle and Depth of Field.
Cameras are very useful when you need to animate the view. For example, you can spin the camera around the object, as well as producing images of the same view multiple times (to show the workflow or procedure of modeling something at different stages, for instance).
Zoom Angle is basically the strength of perspective distortion. The standard setting should be around 45 degrees, but I personally prefer 35 degrees. You can try and get funky with this setting if you wish.

Last but not least, Depth of Field. If you were ever keen on photography, you will know what this means. It is basically the amount of view that is in focus. If you choose f-stop option, it gets easier. The lower the f-stop, the less is in focus. Refer to the settings in Figure 6.

Figure 6

The result (see Figure 7).

Figure 7

This creates a photo effect, simulating a large aperture lens. This further enhances the realistic effect.

Tip: the easiest way to change the position of the camera is to rotate the view to a position that is desired, right-click the camera in the scene and then select the Set Camera to View option.

Realistic Visual Style with Ray Tracing

The other way of producing an image in Autodesk Inventor 2013 is by using Realistic Visual Style with Ray Tracing. This will render the image directly in the viewport, allowing you to interact with the object as you go.

Realistic Visual Style can be turned on in the View tab. Don’t forget to turn on Ray Tracing as well, otherwise you will get a simulated view of the Realistic Visual Style, which is not
accurate at all.

Please note that some graphics cards are not supported. Thus, this feature might not be available. 

Basically, this method of making an image is much simpler than the actual rendering in Inventor Studio, because you get a quick preview in Appearances Editor. That preview is the result  you will get with the Realistic Visual Style and Ray Tracing. There are many preset material styles in the Appearances Editor that can be used, which are quite accurate replications of the actual material.

More advanced users may wish to create their own material styles. In Autodesk Inventor 2013, creating new styles is easy and user-friendly, allowing people to be creative and get the result they desire.

I will start the introduction with the basic setup as follows.

  • A flat plane with Default Material Style.
  • A teapot with Default Material Style.
  • A Default Lighting Style, which can be selected from the drop-down menu in the View tab and modified by selecting the Settings option.

Select Realistic from the Visual Styles drop-down menu and turn on Ray Tracing. In the box that pops up in the bottom right corner, select Good or Best to generate a nice and smooth image. “Interactive” type is just for preview, so you can get an idea of how the scene will appear. This image was generated with “Good” setting and the aforementioned scene in the viewport  is seen in Figure 8.

Figure 8

Tip: Do not rotate or click anything after the bar reaches 100 percent or it will start the process over. Save the image that was just created by clicking on the Inventor icon in the top left corner and selecting Export -> Image, as displayed in Figure 9.

Figure 9

This will generate an image of the scene so you can continue with your work. The scene will be “rendered” once more and the image saved on your hard drive. If you want to avoid the waiting, you can ‘print screen’ your viewport and simply crop out Inventor’s interface.

Appearances

As I mentioned before, material appearances are really easy to set up. There has been a dramatic change in the way material appearances are handled in Autodesk Inventor 2013 compared to the 2012 version. There is a bigger selection of materials; there are more options to choose from; more settings to change. Therefore, people might think it became more complicated.

That is not true, provided you understand how everything works. There are a couple of different material type categories from which you can choose the one that best fits your needs. For this example, I will create a new Material Appearance which will resemble “Chameleon” type Metallic Paint.

Open the Material Appearance editor and click the New Material Appearance button (highlighted in red) and select an appropriate representation from the menu. In this case, it is Metallic Paint.

Figure 10

Many different options will appear in a new window, but for this example I will change only a few:

  • Color: Green
  • Pearl: On
  • Type: Second Color
  • Color: Brown

Let’s leave everything else as is and apply the new material style to the teapot.

Figure 11 shows the result after turning on Ray Tracing.

Figure 11

Notice the brown falloff at the far end.

This is how material editor works with Realistic Visual Style and Ray Tracing. This is only one example of how it can be manipulated to obtain the result you wanted. You can get creative and use various gradients or even images instead of the color I selected (green). This opens endless possibilities to portray a material style. Remember that you might not get the same result while rendering in Inventor Studio, as it uses a different rendering engine.

Scenes

Scenes are a very important part of any rendering process. Without a scene that surrounds the object, it becomes very unrealistic as it is floating in an endless space without support. Scenes also provide shadows that are cast from the object; this enhances the object visibility and understanding of its overall shape and form. It also allows the selected light source to bounce off the scene to create more realistic lighting, thus making the object look more real and the rendered image more appealing.

What I usually use is a vertical “halfpipe” placed on a flat plane. I place the object in the center of the “halfpipe” to create the feel that the object is a finite room. This also creates nice, smooth reflections and gradients.

Tip: If the object is reflective, you can place a couple of fake light sources around it to create a “Studio” feel for the render. Place a plane above the object, and apply a material that has some Self-Illumination.

My default setup looks like Figure 12.

Figure 12

After applying a glossy material style on the teapot, the final result is pictured below.  

Figure 13

You can get really creative with scenes to achieve stunning results. Try different surroundings, different “fake light sources” (such as multiple rectangles placed around the object), different Lighting Styles, and I am sure you will come up with astonishing results, right within Autodesk Inventor 2013.

Mindaugas Petrikas is an automotive and mechanical engineering graduate and has been using Autodesk Inventor for almost four years. He was recently certified as an Autodesk Inventor 2012 Associate and aspires to be an industrial designer and engineer. Mindaugas spends a great deal of time developing kit-cars, for which he is working towards production and sales. You can reach him at http://www.petrikas.net

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