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Paul's Journal

paul
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09/15/2004 23:49 #31225

Off to Off the Wall and the Pink
We are off to Off the Wall for epeep night followed by the Pink for Media Studies hangout night.

09/15/2004 14:45 #31224

Polygon Modeling for VR
Category: design
[size=m]SGI's Performer[/size]
Currently at UB our modeling for the VR environemnt based on SGI's Performer is limited to polygon models. A newer version of Performer (3.1.1) does offer some limited support for NURBS and subdivision models. Version 3.1 also offers a native Maya plugin for Maya 4.5.

[size=m]Creating models for Performer[/size]
Because we are using Performer 3.0.1 I will be talking about polygon modeling exclusively. Just because we are making our final export as a polygon mesh, does not mean that we are limited to polygons when modeling. Examples, the theatre curtains below.

image

image

[size=m]UV mapping polygon objects[/size]
Once your model is created and converted to polygons it is best to texture it using one single texture map. Performer, accets texture maps of any size, but must natively convert them to powers of 2, so it makes sense to start with textures that are powers of 2. E.g. 128 x128, 1024x 1024, they do not have to be proportional e.g. 128 x 512.

Using a single texture map has several advantages over multiple texture images.

[list]
Saves on RAM. Only one textuer needs to load into video am. There is also much less wasted space on a texture.
Easy to organise, one texture file per object
Texture image can span across polygon borders.
[/list]

In the below example I created a model with very low poly cont, textured it using Cinema 4Ds Bodypaint and then exported it using Kaydara's FBX format into Maya 6. The FBX format is a universal 3D model format for moving meshes between modeling and animation packages. Alias just bought kaydara and has promised to continue development of the free plugins. they can be found at

image

image

Brought into Maya for further manipulation and rendering.

image

[size=m]Reducing Polygons[/size]
Reducing Polygons is vital when working in a Realtime environment. The fewer polygon in the final mesh, the better. Maya's polygon reduction tools are excellent at reducing the number of polygons in an object and most often preserve the texture coordinates very well. make sur eto use the heads up display to see details. FOund in Display ->Heads up Display -> polycount

image

image

[size=m]Checking Normals[/size]
Make sure the object has polygon normals facing outward. In maya this is found under Display -> Polygon Component -> normals

[size=m]Obect Axis[/size]
Make sure to center the object axis where you want the scaling and rotation and transormatiosn to occur. In maya this is done by hitting the insert key and moving the axis where you want it to be.

If the model is going to be moved around in the scene, it may be wise to center it at 0,0,0 in the world coordinate system. If it is part of a statiic envirnment, you may want to export it with the transformation already made, so that those calculations don't have to be made by the GPU during processing.

[size=m]Exporting[/size]
You may want to change to z-up in maya. This is done in the preferences as performer is Z up. This can also be done afterwards by performing a rotation on the model. It is, however, easiest to do it at this stage in the process.

Next, enable the obje xport plugin in Maya and export the object to obj. If you have performer installed you can now go ahead and convert the model to a pfb using the pfconv command at the command prompt. This can also be done in linux afterwards. Change to the folder with the obj model, mtl file, and texture file.

Make sure the ob
ject texture is in rgb fo
rm
at. If it is not, simply convert it using phothsop or the gimp and rename all the file ending to .rgb in the .mtl file. Then type the following to convert

pfconv input_filename output_filename

To view your model in performer, make sure you are still in the directory with the pfb model and type
perfly your_model.pfb

Edit the .mtl file and change all Kd calues to 1.0 instead of 0.0 and reconvert if you object appears black.

image


You can find example models from the project here:

09/14/2004 15:36 #31223

In regards to the rss feed
(e:sqb) ,
[inlink]sqb,113[/inlink], to get the full site rss feed you don't need ot log out. You just need to click on the (e:info) journal. The (e:info) journal is also the homepage. I will change the link at the top to say home intead of (e:info) as I think it might be confusing. Anyways, the (e:info) journal has the rss feed fo rthe site. Every other journal has the rss feed for that individual user.

It is the same with statistics. The user stats on the user page are fo rthat user an dthe ones on the (e:info) journal are for the whole site.

Paul


09/15/2004 11:48 #31222

Panos
As (e:sqb) mentioned [inlink]sqb,120[/inlink] Pano's is considering knocking down the Atwater cariage house. (e:matthew), (e:terry), and I are also boycotting Pano's until this issue is resolved. We also eat there several times a week. I am sad to miss the tasty food, but I also don't want elmwood to look like a plaza.

The list keeps growing so fast. Since (e:terry) signed the petition about ten minutes ago there are ten new people.

Here are some great quotes by boycotters:

[size=m]Ian MacDonald[/size]
    Please don't demolish the Atwater House. Please consider obtaining the Forest/Elmwood Parking lot instead. The city can't handle it, it looks like hell and it needs a real owner. There is so little of Buffalo's heydays left except the architecture and the character of the Elmwood strip is a reflection of those days. Parking lots on Elmwood will only make it more suburban and then whats the draw? Lastly it sets the example for other property owners. What is then to stop the numerous slumlords from demolishing their houses to charge for parking? not a pretty sight.

[size=m]Alan Kegler[/size]
You have got to be kidding. Are we as a city loosing our minds. Stop this idoicy immediately before all of our working, eductated people leave the city. Pedistrian friendly (as opposed to car traffic), walkable neighborhoods with magnificant architecture is exactly what attracted my wife and I to this neighborhood. Demolishing buildings like this will only aid in us wanting to move out.

09/14/2004 14:55 #31221

Switch to Firefox 1.0
Everyone should switch to firefox . Iy is definately better than IE in so many ways. I have talked about it many time sn my journal [search]firefox[/search] It is especially ideal if you are a web developer. It's web development tools are such time savers. As always firefox, remains the offically supported browser of elmwoodstrip.com.

Thanks (e:sqb) for the update info [inlink]sqb,112[/inlink]

UPDATE: WOW live bookmarks are mazing. This is really the greatest technology. Check it out. First install the new firefox. Then when you load any users journal, simply click on the little orange rss icon that shows up in th lower left hand corner of the browser. It will let you subscribe to their journal as a live bookmark. This allows you to see all of their entries as live bookmarks in your bookmark list which continually update. You will love it!!!!!