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3D Model Making - Page 1
Written by: Steve Miles
Modelling Programme: OpenFX - Models intended for use in 3D Rad
Page 1 (Modelling Parts - General --- Making a Wheel)
Page 2 (Altering a model so it works in 3D Rad --- Using "Build from Plan" function)
Page 3 (Creating Scenery for 3D Rad)
31st January 2003
Introduction
Firstly, let me start by saying, the models created here were designed with certain characteristics in mind.
My 3D games are created using 3D Rad, a 3D game creation programme. 3D Rad deals with models in a certain way and requires the models to meet certain conditions.
Unfortunately, many models available on the Internet will not function in 3D Rad. This is due to the way the model was made. 3D Rad requires it's models to be made of solids. It is also extremely fussy about the polygons, which must all be the same way. More about this later.
It must be stressed, I am not advocating this is the only way to make a model for use in 3D Rad - It's the way I do it - and it works.
Software
It is assumed you are using OpenFX and are reasonably accustomed to the programme. The tutorials refer to modelling with OpenFX.
OpenFX can be found at http://openfx.org
3D Rad is a 3D developing tool and game creator. It is based on controlling, by independent scripts, the evolution of independent objects.
3D Rad can be found at http://www.3drad.com
Modelling Parts - General
For this tutorial I have decided to create a 3D Tank. Why? Well, I need one for our next 3D game - Tank Storm.
I did some research on the Internet and found some sites with information about tanks. I also found some plans and elevations. I will be using a modelling technique called Cross Section Modelling.
OpenFX has a function called "Trace Bitmap Image". This allows you to import a picture and draw points on it. You can then use these points/outline as a guide to creating your model.
Whenever I model Tanks I always seem to start with the turret. I don't know why, I just do.
First you need to check that the programme is setup correctly. You should be running the programme in OpenGL View. If not, go to "File" "Preferences" "Startup". Select "Start With OpenGL View" and restart the programme.
To ensure that any reversed polygons are spotted as soon as possible, you should set the ViewOpenGL to Single Sided Polygons - deselect Two Sided Polygons.
Begin by starting the "Trace Bitmap Image" function (Build). Navigate to the folder where you saved the pictures and select one that shows a top view. Set "Stretch" to "Actual Size". If the image is bigger than the window, use a graphics programme to scale it down. Remember to do the same with the other pictures if you need to.
Click Add and start drawing the outline of the turret. When you have finished click Exit. You should now have an outline shape in the OpenFX window. Move it around so that it is orientated correctly. Enter "Trace Bitmap Image" again and do the same for the side and back/front profile of the turret - See below.
If you zoom in, on the outline, you will see that it is not square. Don't worry, because we are not going to use this outline. It is purely a guide for our scale.
Right, now we have our guides entered we can start creating our model. On the tool menu, down the right side of the screen, click on Shape. Select Cube and a cube should appear in the window. With only the cube selected. Go to "Actions", top of the screen, and click on "Subdivide". Your cube should subdivide.
Why did I get you to subdivide the cube? Well, I should first explain a quark about 3D Rad. 3D Rad hates it if a model is not made correctly. If you now extruded bits here, there and everywhere you would end up with a very nice model. But it would not work in 3D Rad.
Why? Well, 3D Rad is very fussy about polygons. If they overlap the model will not render correctly. In short the model will not work.
Going back to the cube. Move it to an area where it is clearly visible and select the top and bottom vertices, leaving the middle ones. See below.
Press the Delete key.
When I first started using OpenFX to create models for 3D Rad, I experienced many frustrating hours. Modeling, this way, avoids hardships later when double or even triple polygons show up. I would save you the hours it takes to sort out a messed up model.
Right, back to the model. What we do now is select the remaining vertices and position it, so that the turret-plan is over it - not on it - over it. See below.
It is now simply a case of moving the vertices so they line up with the plan. "Subdivide" sections to add more vertices as needed. Use the "Pan" function to move the windows up and down, it can help to clarify which vertices is which. You should end up with your original square looking exactly like the plan. See below.
When you are happy that your shape is correct, delete the hand drawn plan leaving your "new square plan" in it's place.
Before going any further, make sure that your model has matching vertices. In other words if there are five on one side - it's opposite side also has five. This will help the model maintain it's symmetry. It can also come in useful, later, if you need to edit a part of the model. See below.
Position your plan, so that it is in line with both of the sides outlines. With the plan selected, select "Actions" "Extrude". Left click, in one of the side elevation windows, and press the arrow up key on the keyboard a few times. If the models contours change, as you work your way up, move the necessary vertices to match the outlines. You can also scale the vertices if the whole shape shrinks or expands. Continue until the selected vertices are level with the top of the sides. See below.
Using the Zoom function, zoom in on the model and add any facets or faces needed to even-up the model. If as in this example the top needs extra facets then add them and fill the sections one at a time, to make sure the model maintains the correct shape. On flat, regular areas you can use the "Fill To Cursor" or "Fill To Outline" function to close the model and make it into a solid. Lastly, make sure that all the polygons face the same way by selecting "Actions" "Orient Faces".
If the model turns inside out, select "Actions" "Reverse", to turn them back the right way. Congratulations, you have the first part of your model. See below.
This method can be employed for almost every part of the model. See Below.
Also, by building each part separately it is possible to colour or map the parts individually, which makes it a lot easier in setting up the model in 3D Rad.
It is possible to build very complex models using this method.
To recap: Trace the outlines, build a primitive square, delete the top and bottom vertices, position under plan, shape to plan (adding extra vertices as needed), balance new plan, position, extrude, add extra faces (if needed) and close top and bottom planes (by hand or using the fill functions).
Where the opportunity arises it may be possible to join parts together. If you do, make sure you delete the polygons which end up face to face, before you weld the vertices. If you don't the model will not render correctly in 3D Rad.
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Making a Wheel
Making a wheel, in OpenFX, is easy. First build the hub of the wheel.
Click on the "Shape" tool, right hand side, and select "Cylinder". Select and delete one end of the cylinder. See below.
Select the open vertices and "Extrude" them a little. "Scale" them by 70%, "Origin of Scale - At Center". And move them back so they are in line with the original vertices. "Extrude" again and move the vertices into the cylinder. "Extrude" again and "Scale" 50% and "Fill Outline". Move the vertices back into line. Make sure you aline the polygons. You should now have the hub of the wheel. See below.
Go to "Build" and select "Build Primitives". Select "Torus". An inner tube shape will appear. Scale it and move it, so that it matches and lines up with the hub. Move the hub ends so that they are recessed into the Torus. You now have a simple wheel. See below.
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Want to see some of our 3D models? Take a look at our 3D Model Gallery
Want to see some renderings of 3D models? Take a look at our 3D Render Gallery
SKM Software (c) 2002 - 2003
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