[Development] Is it possible to caculate the irradiance direction vector?

[Eva_Q]

Hi, Vray development team and community. I should've posted this thread in the SDK forum, but I haven't bought a license yet, since I am still evoluating whether Vray is suitable for my project. I know Vray can product the most impressive CG renders. However, one another thing important that I need is to caculate the irradiance direction vector on every pixel and bake them all into image files. I wonder if it is possiable to implement it via SDK. Then, I'm going to make use of them to apply a Dot Product with normal maps in order to shading the details on lowpoly models in real-time. This technique is known as Directional Lightmap in Game Development industry. Due to the insufficient resolution of lightmaps that games commonly use, we can only use THIS technique to rendering the lightmaps with high detailed normal maps in games, but bake all normals shading onto lightmaps. Hope to hear some good news, thanks in advance.

[vlado]

It should be possible yes; there are a couple of ways to do it and I'm wondering which might be more appropriate, but it's doable.

Just to make sure, by "irradiance direction vector" you mean the sum of all hemispheric directions weighted by the irradiance coming from each direction, right?

Best regards,
Vlado

[Eva_Q]

Exactly, Yes. Glad to hear that it's possiable.
Is there any tutorial on how to do that?