# Photorealistic Rendering: How To?

i have started computationally modelling materials from first principles recently, my code of choice being VASP [6.1.0]. Recently i have come across this paper in Nature: DOI:10.1038/s41567-023-01960-5 and became interested in the images rendered. I wish to adapt it to use with a simple crystal structure I used to practice working with VASP.

I have calculated various properties of my crystal like: relaxed structure, band structure, DoS, absorption and reflectivity data. I attach the reflectivity plot of my structure below:

My question is: given this reflectivity data how do i find the appearance my crystal structure will have if/when synthesized in the lab? Can someone detail the exact steps i need to take to do so?

• +1 You can check in the same paper you have mentioned in your question, take a look at the caption of Figure 4, the authors said: 'The photorealistic render of the high-pressure hydrogen in vacuum is made by feeding the Mitsuba2 software github.com/mitsuba-renderer/mitsuba2 with the complex refractive index of hydrogen and introducing a texture to simulate both rough and smooth appearance, following the methodology discussed in this paper nature.com/articles/s41524-019-0266-0 Commented Dec 30, 2023 at 10:11
• @JaafarMehrez i was having a hard time figuring out the working process for this. I am a novice when it comes to ab-initio computations, right now. Thats why i was looking for a proper working methodology in this regard
– F.N.
Commented Dec 30, 2023 at 11:26

Upon posting this question to alphaXiv!, the first-author had commented on the question regarding their methodology:

You can follow the examples on how to render a metallic surface: https://mitsuba2.readthedocs.io/en/latest/generated/plugins.html#bsdfs

In this case,we provided the real and imaginary part of the refractive indices to the program as a function of the frequency in the input file, as specified in the documentation:parts

< bsdf type="conductor" >

< spectrum name="eta" filename="conductorIOR.eta.spd"/ >

< spectrum name="k" filename="conductorIOR.k.spd"/ >

< /bsdf >