Vray Sun not working

Este_Esco · 25 Jul 2009, 17:08

Hey all, I have been having this problem where the render will not make the shadow from the sun that is projected into the object. I have changed my options, my GI, and I have done everything I could but nothing changes the render. what could be the problem?
I´m currently using the demo 01,05.30, the latest edition

thanks in advance

thomthom · 25 Jul 2009, 17:50

Is your GI map set to sky?

What time of days is it? About noon - they can cause shadows no not be very visible.

Este_Esco · 25 Jul 2009, 17:53

the GI is set to sky and the time I have is about 7 a.m ...I have tried to change the time to something other than noon but nothing really happens... weird

thomthom · 26 Jul 2009, 09:54

that is weird.
Though, I think I have heard of cases where the sun doesn't sync properly. What happens if you go into the SKy map and click the Update button?

Este_Esco · 29 Jul 2009, 03:15

The GI (skylight option) is updated, I´ve also tried to mess a bit with the indirect illumination having my first engine always in irradiance map, while the second engine I´ve been trying to render using each one of them, but nothing yet...

thomthom · 29 Jul 2009, 10:10

Do you have a small sample scene where this occur? With just a small cube?

Este_Esco · 30 Jul 2009, 00:07

I´m trying to render a model I did and also have tried with some cubes and the shadow works fine with some tweaks

This is what I have seen so far: When I apply the GI options 1. Sky and 2. Background, both of them are set to sky by default. If you look at the top of the option for ¨Sky¨ the överride sun´s parameter is checked for both GI options, what I have done is to turn off the one from the 2. Background and now seems to work ... however I´ve tried with different files and it does not seem to work constantly. On top of it I have been trying to copy the whole model to a new file (As I think I may have corrupted the file and I don´t know how to fix it, doesnt work even if I change the options) which will let me work with the shadow , but the old file is too big so I think I´ll have to re-do everything including the addition of materials

Thanks ThomThom for your help, it is greatly appreciated!

phmeier · 7 Aug 2009, 05:45

well im with the some problem ...

im trying vray 1.5 and the problem is doesnt matter what i do , render light doens changes. Ive tryied to drag dark and light barre to all dark , and to the maximum light but at the render everything continues the same. The only way i found to change lightness was changing the intensity multiplier value, but the shadows are not moving ,,,,

please, someone help me ...

thomthom · 7 Aug 2009, 06:12

The Shadows controls in SU doesn't affect the V-Ray Sun. The only thing that's linked is the position.
As for shadows not moving - got a sample scene where this occurs?

phmeier · 7 Aug 2009, 08:14

uhm, , well im new to vray ... i dont understand too much these light things .. all i know is that when i configure shadows and hilights in su , it doesnt happens at the render, like shadows position, or the intensity of lighter and darker places,,,

uhmm how i said im new to vray so , sorry about my project !!!!

phmeier · 7 Aug 2009, 08:24

i dont know what ive done but i moved the shadows ,,

so ,, if i understood my problem is solved ? I mean , i can configure the intensity for lighter and darker places adjusting that in sketchup ? Only in vray ? if yes , could u help me eith that ? like how to give a afternoon effect , or mornig ... cause i used to do this in sketchup but i cant do that in vray ...

i think im speaking and speaking and getting nowhere lol !! Lets see if smeone understands me !!

thomthom · 7 Aug 2009, 08:43

V-Ray only syncs the SU sun position. Light and Darkness you adjust in SU doesn't affect SU. It's not a WYSIWYG thing. You have to configure V-Ray.

If you want a morning you set the time to early in the morning. Set it like in real world. When you use the V-Ray Sky it's best to use the Physical Camera. It lets you control the exposure of the image - like you would do in the real world with a photo camera.

In the Enviroment section you have to slots: GI and Background. The GI is the global light in your scene - the background is what you see. They can be different.

For instance: you can use the Sky for GI and use a 360 degree background map for the Background. Or you could use an HDRI in the GI to provide the light from a real world scene. But then you usually don't get very strong shadows.

nomeradona · 8 Aug 2009, 02:20

check if the shadow box is enable in the vray option rollout.

this is a common mistake in vray. say you have the shadow. and now you render, suddenly you change the shadow direction the old shadow direction still the same or sometimes the shadow is even gone. i have read a lot of users had this dilemna.

in order to correct and help the software to not confuse. its better when you move your shadow to create another scene in SU... so you only move from one scen to another scene and Vray will remember those scened having seperate properties in the environment. if you dont create another scene vray will have difficulty.

phmeier · 8 Aug 2009, 13:29

thank you guys ,, i will try !! Im going into vacation , when i come back i post my results !!! If someone else has an opinion , let me know too !! lol!!

1 more time.. thank you !

phmeier · 12 Aug 2009, 18:39

well. . im back and it seems to be working ,,, i mean ive changed my model of document, and shadows are moving .. i got the intensity tthing .. when we use phisical camera , light gets more sensible right ? Or im wrong again ? Well all i know it that im use values like 0.003 at skylight intensity !!

Thank you u one more time !!

NOHD · 17 Aug 2009, 13:26

@phmeier said:

well. . im back and it seems to be working ,,, i mean ive changed my model of document, and shadows are moving .. i got the intensity tthing .. when we use phisical camera , light gets more sensible right ? Or im wrong again ? Well all i know it that im use values like 0.003 at skylight intensity !!

Thank you u one more time !!

you can also try this one:

on the vray options under GLOBAL SWITCHES uncheck the default light and hidden lights

on th CAMERA turn on Physical camera and change the shutter speed to 300 and the Film speed (ISO) into 100.. you can now adjust your shadows using Shadows on SU

EDIT:oops, sorry wrong info.. i tried rendering it once ive changed the shadows by adjusting the time, though the shadows moved, but not in the render in vray..

phmeier · 22 Aug 2009, 21:18

Oh yes .. uhmm i think i did something !! Thak u all !!

Well . here is the final image and two variations for this project who gave me some poblems .. well im studying vray , so all bad things at these images are not coincidences ... lol !! Im uploading it here, cause i think my images doesnt deserves gallery lol !!!