Texture Map Extraction Available in PFTrack 2017

18 Jan, 2017 | NEWS, PFTRACK

Photogrammetry users rejoice! PFTrack’s Photo Mesh node has recently received a powerful new update that allows texture map extraction from a meshed model. Texture maps are masters of deception, creating the illusion of a highly detailed model for the fraction of the computing cost.

We will be exploring the opportunities that are available when exporting to external applications – both VFX and real time – in upcoming workflow blogs.   

So, What’s New?

PFTrack 2017 builds on the updates of last year. Used in tandem with the mesh simplification tools, artists are able to make incredible looking objects to suit their project needs. Controlling triangle numbers in an object while retaining a highly detailed aesthetic has powerful implications for both the real time and VFX workflows.

The Photo Mesh node can now extract: Occlusion, Normal, Colour and Displacement maps during the mesh simplification process. Maps are extracted from the original high resolution mesh then applied to the simplified mesh.

PFTrack’s improved UI allows the user to view the mesh immediately after simplification with its normal and colour maps applied. This allows a comparison to be made between the simplified model and the high resolution original, alerting the user to any necessary changes needing to be made before progressing downstream.

It is important to know the difference between the maps generated in the photogrammetry pipeline, so here’s a quick overview.

Normal Maps

Normal maps encode the surface normal orientation at each texel as an RGB colour. This RGB information is used when shading the model to provide additional surface details, making the low resolution mesh look more like the original high resolution version. PFTrack has the option to create normal maps using either tangent or world space. Configuring normal map settings is important for their use in external software. Normal maps created in ‘Tangent’ use the Mikk coordinate system shared by many realtime applications, Unity for example supports this system, while Mari does not. These are different types of software designed for very different tasks after all, but PFTrack is compatible with both at the click of a button.

Displacement Maps

For real time applications, displacement maps are often used during mesh subdivision to physically adjust vertex positions and create additional detail. Displacement maps can be created in ‘Float’ or ‘Normalised.’

‘Float’ maps are generated as a full floating-point texture that contains its displacement information as positive or negative values along the surface normals in world coordinates. The ‘Normalised’ setting stores the displacement information as a grayscale texture. This setting also writes the absolute displacement scale to PFTracks application log, allowing it to be used elsewhere.      

Occlusion Maps

Occlusion maps are used to outline what areas of the model receive high or low indirect lighting and are available in two forms in PFTrack. The ‘Sky’ option measures visibility of the sky hemisphere at each point, while the ‘Local’ option measures local visibility around a surface point, this is influenced by the angle of surface normal. The occlusion map is crucial in re-creating the look of a high resolution mesh. Objects can appear strange to the eye without proper lighting effects and can easily break the illusion of your 3D assets.

Colour Maps

Contains the colour information about the model’s mesh. Colour maps can be generated in either ‘Balanced’ or ‘Original.’ Creating colour maps using the ‘Balanced’ option evens out any disparity in lighting or exposure that may be present in the object’s data set frame-on-frame. Exposure differences can be hugely problematic when generating colour maps and re-shooting data sets is not always a feasible option. The ‘Balanced’ colour map is the ideal option to produce results under tough conditions.

“Talkin’ ‘Bout Map Generation”

Generating texture maps from a meshed object is achieved in PFTrack’s Photo Mesh node during the mesh simplification process. The workflow is very similar to that found in the ‘Photogrammetry’ and ‘Mesh Simplification and Texture Extraction’ tutorials, but with a few important differences.

The different texture map settings are found in the updated mesh simplification toolset. The maps are extracted during the simplification process, and will be passed downstream for export. More information about texture map settings can be found in PFTrack’s reference documentation.

Finally, there is now no need to create a Texture Extraction node before exporting when using this pipeline. After attaching an Export node, file types and destinations can be selected and modified. Here you will find the individual texture maps, ready to be exported.

To Conclude

Texture map extraction has been a significant update in the Photo Mesh node’s functionality. Combined with mesh simplification, PFTrack’s texture maps have the capacity to save users both valuable time and computing power by creating low resolution models that recreate the aesthetic of a high resolution model. The benefits of these maps can be enjoyed during any project, especially for those with a polygon budget. We will examine the ways PFTrack can benefit different markets in upcoming workflow blogs, make sure to look out for them! See the texture maps below in action, using this 12.7 million triangle count model as an example:

Reduced down to 10,000 triangles:

With normal maps applied:

With the occlusion maps:

And finally, with all texture maps applied:

Have a look at the following posts to see how to use these maps in Unity and Mari.

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