Real 3D FAQ

This page is currently under construction and will be updated as new information becomes available.
Last update: 12/20/95
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General Information

Q: I'm using Windows 95 and Real 2.5 but the program crashes during rendering.

A: Real V2.5 is not fully compatible with Windows 95 at this time.

CSG Modeling

Q: I've created a CSG model of a crystal, but when I render the object there are internal reflections that I don't want.

A: The way to fix this is to finish off your object and then going outside of it's level create a cube or sphere that will completely enclose the object. Once you have this object perform a boolean and of it ( cube or sphere ) and the crystal object.

Spline Modeling

Q: Do spline objects support boolean operations?

A: Currently the only way a boolean operation effects a spline object is as a removal of surface or limit of it. What I mean is that taking a sphere out of a spline mesh using 'boolean and not' will only remove a section of the spline, it will not do the same thing as if you take a sphere out of another sphere and leave a solid interior behind. As the acronym suggests, constructive solid geometry or CSG, works with solid areas but a spline is not solid in this sense, it is only a surface with no interior or exterior area defined.

Animation System.

Q: Why do my skeletons work properly in one direction and not the other when using the animate create skeleton funtion?

A: Currently the interface for create skeleton uses the 'simple skeleton' method instead of the more powerful 'skelton' method. In order to use the full power of skeletons you need to change the animation method to the 'skeleton' method and then create groups from the mesh as it's target. This is fairly easy to do.

• Create the spline object that you want the skeleton to effect and apply the animate/create/skeleton menu on the object. Do not update the animation system by hitting 'u' or the menu item.
  
  
• Go into the created level and select the 'simple skeleton' level, use the modify/properties/animation item to change the method to 'skeleton'. Again do not update the animation system yet.
  
  
• Select the mesh object that you wish to modify and begin creating the sub groups that you need to modify the object. To make a subgroup just hold down shift and ctrl while draging a box around the cross sections that you want to have modified. Each time you create a sub group you will need to reselect the spline object in the selection window to create another one. Once again do not update the animation system.
  
  
• Now everything is set up but you don't want the skeleton to modify the original object so multiple select the skeleton method and all the subgroups and use the create/boolean/or menu item to group them all under on level. Now update the animation system by hitting the 'u' key or selecting the update menu item. You should now have a completely working skeleton method in all directions.
  
  

Q: Why do the skeletons created by animate/create/skeleton not work with primitives properly.

A: Again this is due to the fact that 'simple skeleton' is being used instead of 'skeleton'. In order to fix the problem, simply select the 'simple skeleton' method and use modify/properties/animation to change the method to 'skeleton'. Press the 'u' key to update the animation system and add the proper tags to the objects.


Q: Heirarchical skeletons do not seem to work properly.

A: In the current version available the heirarchical skeletons do not function properly.

Materials System.

Q: I'm trying to morph between several materials that have different positions but it doesn't seem to work.

A: Real V3.3 has a problem with the material morphing system that causes the primitive not to be processed correctly, bug fixes are in progress.

Rendering System.

Q: I have a complex CSG object made out of glass but it is not rendering correctly, why?

A: A possible cause of this is the render settings recursion level. This control will modify the maximum number of rays used to create a single pixel. In a scene with ground and a glass sphere: seeing the ground through the sphere requires 3 rays, one for the entry of the sphere, one for the exit from the sphere and one to hit the ground. If you put a second sphere inside the other sphere you have complicated things, it is not require that you have a recursion depth of 5. This is because it take 2 rays to trace the first sphere, 2 rays to trace the second sphere and 1 ray to hit the ground. This keeps going up with the complexity of the object that you are making.

NOTE: If you take the sphere in the original example and cut it in half by performing an 'and' on it with a plane you will have to increase the recursion level by one. Sound confusing? If so this is the reasoning, saying that you cut off the front half of the sphere, you still have the sphere object present in it's complete form but since the ray hits the front of the sphere and it is not entering or inside both the sphere and the plane ( the and part of the boolean ) the intersection is ignored. The ray is followed further into the scene and hits the plane, this point is entering the plane and inside the sphere so it is a valid point and treated as such, the ray is then followed through the interior of the sphere to the exit point at which a final ray is created to hit the ground object. That is a total of 4 rays even though you didn't change the visible number of hit points.

RPL System.

Q: How do I learn RPL?

A: The best way to learn RPL is to purchase a book on it's parent language Forth. Finding these books requires a bit of work though. Right now Forth still maintains a fair following but it is not 'mainstream' enough to find in your local book store commonly so finding a technical book store or one with a complete selection of topics is required.


Q: Why does Real use Forth as the basis of it's programming language?

A: RPL is based on Forth for a number of reasons:

• The number one item is that RPL can be a fully functional language without taking much space. Forth is an extremely compact language and can be extended as much as required without demanding high overheads in memory requirements.
• The language is extremely quick for what it is, without a professional quality external compiler and various linking methods, other packages normally use slow and bulky interpreted languages for scripting. Another limit in other packages using so called scripting languages is that most of them only allow the language provided to access one or two areas of the program, while Real gives you almost complete access.
• One other reason that the choice could have been made is that Forth is one of the only languages that allows you to work at a completely modular level. A word in Forth can be built in or defined by the user, once the user defines a word it is used the same as any other word in the language. This means that with a little careful thought on the programmers part all of the words that he creates in his projects can be used in other projects, in this way he is making his own language particularly suited to his/her own needs. Other languages can do this but usually not the ones chosen as scripting languages for other packages.

Amiga Specific Information.

Windows Specific Information.