ATI TruForm

TruForm is a graphics texture technology created by ATI and employed in DirectX 8 and OpenGL graphics cards, on both Mac and Windows. The technology was first employed on the Radeon 8500, but being neither part of specifications of DirectX and OpenGL.

Overview

Before the adoption of pixel shader-enhanced bump mapping methods such as normal and parallax mapping that simulate higher mesh detail, curved 3D shapes in games were created with large numbers of triangles. The more triangles are used, the more detailed and thus less polygonal the surface appears. TruForm creates a true curved surface using the existing triangles, and tessellates this surface to make a new, more detailed polygonal model. It is designed to increase visual quality, without significantly impacting frame rates, by utilizing hardware processing of geometry.

TruForm was not significantly accepted by game developers because it ideally required the models to be designed with TruForm in mind. To enable the feature without causing visual problems, such as ballooned-up weapons, the models had to have flags identifying which areas were to be tessellated. The lack of industry-wide support of the technique from the competition caused developers to ignore the technology rather than splinter their user base.

In later version of Catalyst drivers, the TruForm feature is removed.

Beginning with Radeon X1000, TruForm is no longer advertised as a hardware feature. However, Radeon 9500 and higher (as well as hardware supporting Shader Model 3.0) include Render to Vertex Buffer feature, which can be used for tessellation applications.[1] In the case of Radeon X1000 series, it supports binding up to 5 R2VB buffers simultaneously. Tessellation as dedicated hardware returned in Xenos and Radeon R600 GPUs.