After many years of verification, RiMM has come to the conclusion that a photorealistic environment is not necessary. The important thing is that there is no lie in the field. It is most important that you do not feel uncomfortable when you experience it, that you do not look at objects unrelated to the disaster, that you can easily understand the situation of the disaster, and that you can easily convey the essential fear. The conclusion is that photorealistic environmental reproduction cannot achieve the purpose with the current hardware. The virtual space is a virtual space and cannot be completely reproduced as the real space.