Ignition capabilities

[Craig Jolly]

Several questions regarding the UGC engine -

1. Does it support Opacity Maps?

2. Can we have reflections?

3. What is the recommended polygon limit?

4. What is the recommended texture map size and number?

[KenMaffei]

1. Ignition does support transparency in several different ways. However, transparency in real-time engines is always problematic.

Opacity is done by using an alpha channel in your diffuse map. In other words, the exporter does not export the opacity map channel separately. So you would put a 32 bit .tga file in the diffulse map channel.

If your alpha channel is made up of pure black and white, no greyscale, UGC will have no problems at all with transparency. However, greyscale transparency can be problematic, as it is for all real-time applications. Although we have a few ways to deal with greyscale, we have not yet determined how we want to expose this for the Developers. We are looking to see how we might do this. I can tell you though, that moving objects that have greyscale transparency will not be a good design decisions.

We'll keep you posted on the state of including greyscale once we determine how we want to add it to the Dev tools.

2. We don't support real-time reflections or shadows at this time. You'll need to bake these into your textures. Generally speaking, any effect that requires multi-pass rendering will be detrimental when displayed on the Alioscopy monitor due to the need to render 8 cameras per frame.

3. Polygon limit is always a tricky question. I would probably try to keep it below 20,000. Remember that the end use will be able to add props to the template. Long text can bump it up pretty quick, for example. Also, video textures are pretty resource intensive, even though we've implemented them as separate threads, so ultimately it's going to be the user's issue along with their system's capabilities. Smart texture design is your best friend!

As a note, if/when this product gets rolled out for regular 2D monitors, you will have way more latitude in terms of what you create. It's really the 8 cameras for the 3D monitor that is restrictive here.

4. Texture maps for games are always in powers of two in width and height. However, UGC will scale your texture up to the nearest power of two if you supply one that isn't. Although it is not the best practice to supply arbitrary texture sizes, it does seem to work fine with UGC. Note that the width and height do not have to be the same. You could have 1024 x 512 for example. We do not recommend sizes greater than 2048. As a benchmark, 1024 is pretty standard for games. But if you are doing multi-subobject mapping and have a particular texture on a small area, there is no need for it to be that large. You can just use common sense.

A final point on textures is that if you are not using an alpha channel, you should not use 32-bit textures as the alpha channel would take up space in texture memory for no reason.

--Ken