



Also the choice of the models is important in Activeworlds. Here you will read why objects need to be "low polygon" in a realtime 3d environment. Stacee(#319521) used in her classes some examples of car models to show the difference between low polygon and high polygon models.
Visit also AWSchool 81S 165W , where you have a 3d view of Stacees 3D classes.




What do you need to know before you start using models ?
1. Models on the internet : 
Be prudent when you read "lowpoly model" on the internet: a lot of 3d models on the internet have less polygons than some highdefinitionquality models but still are not adapted to 3d realtime environments. That's why you better search on the internet for "game 3d models" or "realtime environment 3d models". 
2. What is a low poly model ? 
Using a low poly model means that it is a model for which all efforts are done to get to a minimum of polygons : these are the number of triangles which are used to make the model. Almost all 3d programs divide their objects into triangle surfaces , this means that each square surface consists of 2 polygons (or 2 triangle surfaces). 



Which type of models do you use ?
For this you need to take these things into consideration : 
1. Complexity of the object 
You need to consider that a kitchen table is less complex than a piano, so the table should be modeled with less polygons. 
2. The importance of the model in your scene 
Use as many low poly models as possible : is the model used as background ? Then make it low poly. Is the object used very often in your world (trees, chairs , lamps) ? Then make it as low poly as possible. You can use objects with more polygons for (rare) objects which draw the attention in your world. Example : a highpolygon christmas tree ,but as an eyecatcher in your scene. Coffee cups and plates: this is less important, make then low poly. 
3. The type of world : 
Will you use your world to have a lot of visitors in it at the same time, or is your world a building world ? If you have a building world, then you won't choose yourself, but the builders will of course choose the highpolygon models, so try to offer low polygon models in your objectpath. If your world is not a building world , then you can easily spread or limit the highpolygon objects . 



Models optimalisation in your 3d world :
5 Guidelines for making a good model : 

1. If you don't see it , don't model it 
Just model what you see. Don't model the inside of a box or a cylinder that you can't see. Details upon a model should better be made with textures instead of modelling it with extra polygons. Start with primitives (spheres, cubes) before going into detail. 

2. Accomplish details with textures 
Details upon a model should better be made with textures instead of modelling it with extra polygons.(e.g. the numbers on a clock). You can create depth in your textures by using shades and darker and lighter parts.(see picture of this cabin). You can can also use masks instead of using real geometry in the modeling program. (e.g leaves of trees) 
But try to avoid making a high polygon model in combination with masks, the two together will create even more lag. 




3. Count the number of polygons 
How many polygons should a model have ? 
A model with 10.000 polygons : this is too much, even for a large building. 
A model with 1.000 polygons : is still a lot, and used only for complex or large models. 
A model with a multiple of 100 polygons : this is better , acceptable in a 3d world. 
A model with less than 100 polygons : this is a good object . 
But all depends on the complexity of the model : a table can easily be made with less than 100 polygons. An apple or banana will need some more polygons, although these objects are smaller. For large objects you can go more into detail than with small objects. 

Details : be careful with the number of polygons, the more flat surfaces, the better. Avoid modelling too many details. For instance , for a car , avoid too many polygons on the wheels ,and instead of modelling the dashboard, you can use a simple picture. 



4. curved surfaces should be moderately smooth 
If you use models with curved surfaces (cylinders, spheres), you need to check if there haven't been used too many edges and faces to make a smooth rounded surface. Models which are a bit less smoothened are better for a realtime 3d environment. The perfect circular shape in realtime 3d is rather angular, and should be a slightly less smooth. As an example : to make stalks for plants, it is better to use 6surface cylinders instead of 16surfacecylinders. 16 sides for a stalk of a plant is excessive. 
Some modeling programs are based on nurbs, which usually start with an excessive number of faces, and an excessive number of polygons. Nurbing programs are not made for realtime 3d environments. 

example of nurbing : http://www.3drender.com/jbirn/ea/HeadModel.html 


Example of a model made with a nurbs modeling program. 



5. avoid too many subdivisions on flat surfaces 
Don't use unncessary subdivisions on a flat surface : a twosided panel has 4 polygons (2 polys for each side). If the panel model has 64 polygons, then don't use it , make a panel with less polygons. 
Extra subdivisions are a waste of polygons, unless in some modeling programs, you will see that some surfaces are subdivided into more polygons in order to optimize the lighting upon the model. In Accutrans you can reduce the number of polygons. 




Some examples ....
This sports car is an example of a poor realtime 3d model , because it has too many polygons, and doesn't follow the 5 guidelines for a optimized model.
This policecar is already better , but still doesn't follow all 5 guidelines: there are still too many polygons on the flat surfaces and around the wheels, and some details can be replaced by textures. This can be optimized , so that the object loads faster in the 3d environment.
This white car is an example of a good realtime 3d model , as the 5 guidlines are respected. For the dashboard you can use a simple texture instead of modeling it all.




More tips for object optimalisation ...
1. collision off for avatars 
If you use avatars in your world, the framerate in your world will be lower , knowing that each avatar is ± 15002000 polygons, if there are 30 visitors in your world, this will already be 60.000 polygons without the scene, so the scene should be low polygon if you want to do events for lots of people. But you can make that avatar objects "collision off" : you can use the action command, but you can also do this already in accutrans, before uploading into your object path. The disadvantage is however that at the same time, the model will be "solid off ". You can't use the collision off for masks and transparency. If you want to use transparency, you can use the command opacity. 

2. wireframe view 
In almost all modelling programs, also in accutrans, you can view the number of polygons of each object. But you can't view the number of polygons when building in Activeworlds. But there is the possibility to view the world in wireframe . For this your need to select : 
Options  Settings  Video  Wireframe Rendering . 
When you approach high polygons objects, you will probably see a lower framerate. 

