The Texture Advisor is an auxiliary tool that will help you choose the right texture size for every model. The results are not 100% accurate, as there are many factors that can impact in the Texel Density calculation, but it will give you an estimate of the best texture size for your models.
It does calculate the optimal Texture Size based on an optimal UV Unwrapping and UV Packing.
New Analyze Mode
Uses the Geometry Topology to calculate the Texture Size and optimal Texel Density. It does not require the object to have a UV channel setup.
It is slower than the Quick Mode as it uses additional UV information to produce more accurate results. In order to produce meaningful data, the objects must be already unwrapped.
You need to specify the UV Channel from which the data will be collected. If the object has no UV data in the specified channel, the results will be empty.
Same as the Unwrapped mode it uses the UV information, but in order to produce meaningful data, the object must be already unwrapped and the UV Shells must be packed.
The information produced in this mode is meant to be used by the Scale tool, as it preserves the UV layout.
Same and in the Main UI, it is the ratio between the Geometry Area and the Pixels Area expressed as squared root.
Wasted UV Area
It is the UV Area that won't be used by the Shells themselves, and can represent empty area or area used by the Shells padding. This value is usually between 15% and 30%.
Once you have setup the Geometry/Pixel Ratio and the Wasted UV Area parameters, click on Process Geometry wither all or just the selected models to see the results. It is not required that your object have already being unwrapped, nor to have an Unwrap UVW Modifier applied to them.
The name of the object.
The total Geometry Area of the object in World Units.
The Total Pixels Area needed to texture the object using the specified Geom/Pixel Ratio plus the Wasted UV Area percentage.
The optimal texture size to cover the required Pixel Area.
Nearest Pow 2
The nearest power of 2 texture to the optimal Texture Size.
Used UV Area
The optimal UV Area used by the UV Shells if normalized with the given Geom/Pixel Ratio. The range goes from 0.0 to 1.0. Values over 1.0 means the texture size needs to be larger than the nearest power of 2.
The optimal Texel Density to fill the nearest power of 2 texture. If this value is larger than the specified Geom/Pixel Ratio, it means that there should be enough space in the texture for this object. If this value is lower than the specified Geom/Pixel Ratio then the texture size might need to be larger than the calculated nearest power of 2 texture size.