3D Modeling & Rendering

(Introduction to creating three dimensional computer models and images)

History:

3D-Rendering got its beginnings when government contractors were hired to make a mathematical computer simulation in 1966. A company called MAGI was tasked with simulating how radiation coming from an active radiation-source would affect and interact with objects. How much radiation did this or that object absorb?

Later when the program was finished the concept was cleverly changed by some of the mathematicians so that the simulated radiation was light and the source was the sun. After adding three dimensional models one could have the computer create a visualization of an entire scene that never existed but looked incredibly real. This was called ray-casting because light could be traced from the simulated camera to the simulated sun. It wouldn't make sense to send out rays in every direction from a simulated sun and only care about the rays of light going to the artificial camera. Because of this the only rays that are calculated start at the camera and work backward. When the rays get to materials such as glass or water they actually imitate how light would interact with these surfaces. As you can imagine, the process was very intense for the computers of the day and took great computational power.

My 3D rendered image of an F-15C fighter aircraft zooming over the pyramids

By the 1970's the inventing company had moved into everything from computer animation in television to working on the science-fiction movie TRON. The late 1970's brought better ways to calculate rendered scenes called ray-tracing. Added were better shadows and reflections along with much longer computational times. By 1985 MAGI was out of business.

In the early 1990's home computers were becoming powerful and many graphics enthusiasts were making a hobby out of 3D-rendering. At the time everything was tediously described in a text file to explain the shapes of the models and computer scene. It took some imagination to type out what a scene would look like by way of numbers and locations. The process was then started from a command line and days later an image was available that looked photorealistic.

Today our home computers are amazingly powerful compared to the first renderings. We are able to create whole worlds in a drag-and-drop computer fashion. We can make visualizations of virtually everything in our minds and not have to wait days for the results. Remember that in simple terms modeling is where you create or put together objects in the computer. Then in rendering you let the computer calculate the light rays to make a raster image that looks like something photo-realistic.

Freeware Rendering Program:

Alright so how do you actually do 3D rendering? Let's start slow by using a freeware program called Now-3D. This program has the appearance and many basic functions of the expensive rendering programs liked 3D-Studio, Bryce5, Cinema-4D, or Maya. While it may not be as powerful as those programs in that list it's a great starting place. I have noticed however that the program Now3D didn't have an immediate import for DXF. This is handy when you get proficient at rendering because there is a world of free 3D models on the internet already created for you. To import DXF with this program a plug-in is added separately. Download the main program from my link below and then let's begin with our first rendered image in the following steps.

Now-3D Rendering Tutorial:

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Click here to Download Now-3D v1.2.700 by Giuliano Cornacchiola
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1) First install the Now-3D program.

2) Start the program with the N3D Professional icon from the start menu. Notice you are given four windows when the program starts up. Three of these are the top-view, right-view, and front-view. The top left window is the camera's view but blank at first. That is where you will preview the rendering process. Notice the artificial light (little yellow sun like symbol) and artificial camera to simulate recording this 3D world with geometry, viewpoint, texture, lighting, and shading information.

3) In the top menu click Object and then submenu Add. Choose a shape. For this tutorial left-click Sphere. Then left-click the Get Mesh Sphere button and the program will create a 3D mesh.

Just a note but a mesh is an object made out of triangles (sometimes you can't see the actual trying but the rectangle in the shapes). In most modeling programs the models are made out of triangles. The smoother the object the more triangles involved. Each point of a triangle is called a vertex.

4) Go up to the menu labeled Preview and choose submenu Z-Phong. The Sphere turns green. That is because the default color for the sphere was green. You have officially rendered your first image and it's that easy. Notice how the light reflects off your sphere.

5) The appearance of the sphere is controlled on the panel to the right labeled SCENE. In the lower window on the right side labeled Objects (Sphere) left-click on the row labeled Color. When you clicked on the row then a button with a few dots appeared to the far right of the row "...". Left-click on that button with the dots and change the color of your sphere to red. Then click OK to accept the new color.

6) Go back to the Preview menu on the top and choose Refresh. Your object should change to the color you chose.

7) Let's put another sphere on top of the one we just rendered. Go back up to the top menu and left-click Object and then submenu Add again. Left-click the choice of Sphere and then Get Mesh Sphere again.

8) Now you will need the 'select' tool. Go to the top menu and choose the white arrow icon. Left-click the sphere bottom left window. We are going to raise one sphere and put it on top of the previous one. When you select any object it will show red brackets around the object. On the top menu left-click the move tool. This icon looks like two small red squares connected in the middle with a line-like arrow. This is to show a square has moved I assume. In the bottom left window move one sphere upward till it rest on top of the bottom one. Now you can choose Preview and Refresh again but your camera is too zoomed in to see the top sphere.

9) Left-click the white arrow icon in the menu again to get your 'select' tool. Use the select tool to choose the camera in the bottom left view of your scene. The camera icon will show red brackets to indicate it is selected. Use the 'move' tool again (the small squares icon with the line between them) and move the camera to the left which is simply moving the camera outward so it can see both spheres at the same time. Now we will refresh our rendered scene again. This time do it faster by pushing function key F5 on the top of your keyboard. With any luck you can now see both spheres in your scene. Continue to move the camera and press the F5 function key until both spheres are rendered in the frame.

10) If your camera becomes hard to select because it is nearly off the screen then try this. Choose the hand icon from the top of the screen. Go down to the bottom left window and push the view left. This is a handy way to adjust your own view of the scene.

11) Change the color of the newest sphere as before. In the lower window on the right side labeled Objects (Sphere) left-click on the row labeled Color. When you clicked on the row then a button with a few dots appeared to the far right of the row "...". Left-click on that button with the dots and change the color of your sphere to red. Then click OK to accept the new color.

12) As you've seen moving objects around isn't that difficult. But many times you'll need to use all the views to assure you get the objects where you want them. Let's see if we can make a red snowman character out of our simple objects. Let's add eyes and a mouth to see how the placement of objects works with depth this time. Begin by creating more spheres as we have done in the previous steps. You can leave them green this time.

After making spheres use the magnifying glass icon to zoom and look closer at the head of our snowman. This works in any view you choose. You will also need the hand or glove icon to pan the window around. Lastly there is an icon that looks like a three layered squares for scale. Use scale icon to shrink down the spheres but you may have to select them individually with the white-arrow selection tool first. Next move the sphere and be sure to keep track of it in all the views so you know where it truly is on the snowman. Depth can be tricky if you use only one view. Press F5 after each object is moved to see how it appears in the camera view in the upper left.

13) When you are ready to create your final image look up at the icon bar. There you will see an icon with the letter "N" above the word "3d". Push this N-3D icon and the program will render your image into a smaller window. Lastly go up the disk icon in the upper left. There you can now save the images you have been working on.

We are now complete with our first simple 3D rendering project. The concept in most 3D rendering is that you use very fundamental shapes to create both simple and complex objects. Later you can retrieve the plugin for this program to import DXF or use another program so that thousands of free models already build on the internet can be used. If you found this tutorial easy than let's move to the next rendering example on the next page!

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Onto next level of Rendering >>

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Written April08 and updated Sept08 by Tracy Rose