V-ray car rendering help


#1

I’ve been working on this project of car studio render, using around 8 different lights, everything’s been working fine and till now I’ve rendered 4 different shots but in this one I can see at some places on the ground some block shaped artifacts I guess? I don’t use v-ray much and just decided to start learning it so this is one thing I haven’t been able to figure out, I’ve tried changing lighting, materials, remapped uvs, changed render settings but can’t really understand why I’m getting this.
BMW_M2_Coupe_2016_rear_test
BMW_M2_Coupe_2016_rear_test_marks
If you look closely, you can see some blocky shaped spots there.


#2

They are very faint, but I’m not sure how you would fix this without a lot more work and render-testing. I imagine you’ve plop-rendered those areas while changing settings to no avail?

Since these are just shadow-areas, can you fix it in post? Can you blend it in Photoshop or something?


#3

I am guessing this has to do with “the position” of your HDRI image and Lights…

Here is a image of what I am trying to say…

As per my image - in 3d space around 4 shadows would be created on an object with 2 hdri light sources and 2 vray lights. I guess you understand now where the extra shadows would come from…

00

1 - Render out an image with only your HDRI (Switch off other lights)…
2 -Render an image with only your scene lights (Switch of your HDRI source).

Post it here, If I am wrong about this we could get a better insight at what exactly is causing these shadows.

The Solution -

Place your lights exactly in the direction where your hdri lights are with 0,0,0 as center…

Just like in a day scene - How they match the vray sun to hdri…

Here is a link to explain better about a single light source in HDRI and and a Single vray light -

https://vimeo.com/57433530

I am afraid since you are using 8 light sources - you would have to align 8 cameras as per the tutorial and place your lights exactly where your hdri image’s light sources are.

Note - Use same number of lights as per your hdri image.

Do post your renders… would love to help :wink:


#4

No I didn’t plop rendered those areas I setted the whole scene with ipr render first, this was a complete render without any messing around with settings in between, I did tried changing light positions and all but didn’t help.


#5

Thanks for the explanation, I understand what you are explaining me here, I did use an hdri first but it was just for setting materials and all, I turned it off because I coudn’t exactly get the output according to my preference and so I set the whole scene with v-ray lights only, without any hdri, but yeah I’ll give it a try with different camera angles and see if it works, though it should work I think because its rendering just fine with other camera angles.


#6

@Pinokio28

I think he is talking about the bucket like artifacts (edges perfectly horizontal and vertical) that are visible very faintly.

@Akshat Sharma

Are you using buckets at all (as image sampler or in the irradiance map)? Do you use distributed rendering?


#7

Yeah I am using bucket sampler, shading rate is 2 but no, I’m not using distributed rendering