HDRI and Vray

[Rconce01]

Over the weekend i started using some free HDRI maps from http://www.hdrimaps.com/ and i noticed an improvement in the quality of the rendering but i am wondering what should be involved in the selection of the hdri map for a scene. Are there some basic things you need to look for based on the typs of rendering you are doing for example an exterior rendeing in a well illuminated place vs an interior night shot. I am really new to this vray and the hdri maps but i think the quality is amazing i just need some guidance in how to proceed with this combination.

 

Thanks

[Christopher Nichols]

Over the weekend i started using some free HDRI maps from http://www.hdrimaps.com/ and i noticed an improvement in the quality of the rendering but i am wondering what should be involved in the selection of the hdri map for a scene. Are there some basic things you need to look for based on the typs of rendering you are doing for example an exterior rendeing in a well illuminated place vs an interior night shot. I am really new to this vray and the hdri maps but i think the quality is amazing i just need some guidance in how to proceed with this combination.

 

Thanks

 

When it comes to lighting with HDRs there are two main things that matter, and they matter in different ways. Specular light (reflections) needs a lot of detail (resolution). Rarely, will you need anything above 5k, but I have used giant ones. When it comes to Diffuse light, what matters most is the depth of the image... 10 to 20 stops makes for high quality. Things will look washed out under 7 stops. Keep in mind that stop also matters for spec and res for diffuse, but not as much. A good quality HDR is 15+ stops, and 5k...

 

Now... here is the key to those stops. How deep they are mainly counts on the low exposures. Meaning, when the light sources go really really low and you can start to see the filament in the bulbs... then you got yourself a good HDR.

[allwhiz]

material library loading on max8 from previous versions

anybody can help me on how to load .mat or .mtl extension on 3d max?

coz i have material library on previous max, and on max 8 it cat be loaded.

[trino]

material library loading on max8 from previous versions

anybody can help me on how to load .mat or .mtl extension on 3d max?

coz i have material library on previous max, and on max 8 it cat be loaded.

 

try to keep the main subject, yes you can loaded in max 8 coming for previous versions, just put it in the matlib folder.

 

Now to the post, which library has good HDRI mainly for exteriors Christopher?? i have been looking the Dosch libraries and the look good, specially the HiRes ones.

[Rconce01]

chris how do you determine if a particular hdri map has those values you specified ....do you check it out in photoshop or in max? Also do you use additional lights along with hdri maps?

 

thanks for the input

[Christopher Nichols]

chris how do you determine if a particular hdri map has those values you specified ....do you check it out in photoshop or in max? Also do you use additional lights along with hdri maps?

 

thanks for the input

 

The best way to check is to open the file in something like nuke or HDRshop. Then run the cursor over the bright spots like light sources or the sun. Overcast sun, or sunset should be around 200 or so. Bright sun should be around 25,000, but I have seen some from Paul Debevec that measure 10 million... Those are hard to manage, even in Vray. General sky should be around 1 to 3... light sources like a light bulb around 10 maybe. If nothing goes above 4 or so for an outdoor scene, it is pretty low quality. Good IBL lighting is a challenge... not really plug and play like people think.

 

For your second question. The better the HDR, the less need for additional light. On my first DVD, I use a lightsource to supplement the sun. Works great. But with higher quality HDRs, that becomes less needed.