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WChestnutt
04-23-2003, 03:15 PM
Hi,

i need to set up a scene for a car so it gives good lighting, and a nice realistic reflection on the metal, i have tried many ways of doing this in the past, i have tried hdri, having a plane next to the car so it gives a reflection along one side of the vehicle, and lots of others but they never give a decent result.

i have seen some really nice hdri renders, but when i try it the reflection comes out really sloppy...
are there any good ways of seting up a scene which produces nice lighting and good reflection on the car??

Thanks,

Will

Cole
04-23-2003, 04:06 PM
download a good outdoors hdr probe from:

http://www.debevec.org

then get Hdr Shop (find the link on that page...), go get this plugin. Use that plugin to fake hdri lighting in your scene, then use the Imageworld plugin to get good reflections! To use imageworld hit ctrl-f5 and then where it says "add environment" pick imageworld, then hit ctrl-f4 to open up the image box, find your hdr picture on your harddrive... go back to the other window and set your hdr for the imageworld and have fun rendering. You dont actually even need radiosity turned on for this to work and you still get nice (and fast) renders :)

Cole
04-23-2003, 04:07 PM
Forgot to mention... make sure anti alias is set to enhanced medium or better :P and you might have to play with the heading offset value to get your lights and your reflection to line up right (tho ussually u dont)

WChestnutt
04-23-2003, 04:36 PM
I'll try that thanks!,
i didn't know you could do it without radiosity!

Cheers,

Will

Scott 3d
04-23-2003, 04:41 PM
Hey check out this tutorial by Savinoff - great cheap way to get good reflections and highlights.

http://www.savinoff.com/home/?chapter=extras&part=tutorials&section=beginners&nav=nn

digital_red
04-23-2003, 10:23 PM
Take a look at the A5_Concept.lws in the MeniThings folder. Its a good example of a simple studio setup.

WChestnutt
04-23-2003, 11:20 PM
Thanks,

i tried the audi scene with my car but it just looked weird...

that tutorial was well hard!!! it didn't make it any easier by not having any pics of what to at the first few steps (setting up the scene).

this is the best scene setup i've had so far...

http://image1ex.villagephotos.com/2194157.jpg

it has a plane next to the car making reflection, and it's lit with hdri.

Thanks,

Will

Cole
04-24-2003, 04:07 AM
for really good hdri reflection results you must use an image probe for lighting, not just a plain spehere or whatever. You can get a good one from that link in my first post. Heres the basics of what you need to do:

First make a really really big circular disc floor for your car to sit on, like 10km or larger (i made mine 45 miles...). the edges should curve upward to about 3km (or higher if you plan to use a low camera angle. anyway it should look like the attached pic.

you can give it any surfaces you like, but dont overdo the reflection and try to keep it a nice pale colour (default grey is good) Dont give it any specularity tho or it wont look good.

anyway load in your car model in layout, set up the camera how you want it etc and then load in your big sphere. Now hit shift-L and then p to open the lighting box, set the main light intensity to something like 25 or 35. distance light works best, although you have to make sure your floor isnt blocking the light. if it is just change the light to a spotlight and move it alot further away from your car.

Now you need an image probe from debevec.org. I recomend the "campus probe" one, anyway download it and then go to layout, hit ctrl-f4 and then load and find the probe you downloaded. Ok now the important part that makes this work. hit ctrl f5 to bring up the backdrop window. Where it says "Add environment" pick ImageWorld then double click on "Image World (no image)" and where it says "lightprobe image" pick your lightprobe. You can lower the brightness a little since your using a normal light also if you want, but i would leave it at 100% until i see if it needs to be lowered. Now you need to open the global illumination box, go to the lights tab and find the button on the left for "global illum" Click it and you'll get a dialoge with a bunch of options. First thing is to enable radiosity. Monte Carlo will work fine, but you need to increase the rays per evaluation. 7x12 works well for most things, for better quality use 9x27 but be warned render times increase dramatically the higher quality you use. While this panel is open change the ambient intensity to 0 and you should be ready for a test render. Hope i didnt forget any steps...

Now radiosity is really really slow so you might want to explore some ways of faking it, but you'll have to experiment and see what fake methods work for you. Personally i recomend exporting lightprobe information from hdr shop but some people get excellent results with the overcaster plugin also.

Cole
04-24-2003, 04:08 AM
ah i forgot one thing, make sure anti aliasing is turned on.

WChestnutt
04-24-2003, 11:19 AM
that is what i have done in the above pic, i will try the campus light probe.

Thanks,

Will

Cole
04-24-2003, 11:52 AM
make sure raytraced reflections are on in render options also and your surface has a good reflection value(but not to high).

WChestnutt
04-24-2003, 01:54 PM
:thumbsup:

WChestnutt
04-24-2003, 07:14 PM
ok, i just finished some test renders using the campus probe, i think the results are the best i've had so far :thumbsup:

http://image1ex.villagephotos.com/2313523.jpg

the image has an "hdr exposure" filter, with a white point of 3.07 and black point of 90%, also i have turned the contrast of the image down a bit.

can you please tell me ways in which i can improve it's quality?!...

Thanks,,

Will

Cole
04-24-2003, 07:41 PM
Its starting to look good, maybe add a distance light with a low setting (15-25%) and lower the gi level a little. main thing you need to work on now is surface settings. Work on simulating the fresnel effect in your reflections. atm i cant remember the link to a good tutorial, but you should be able to find one or just use this quick way to do it. I attached a screenshot that gives you a basic idea of how to make a quick and dirty fresnel shader.

Cole
04-24-2003, 07:43 PM
and the second image: just click on the little box with a T in it beside the reflection settings to get this window:

Cole
04-24-2003, 07:48 PM
Quick explanation of what this does. Basically just pick any colour you want, set spec really low (your using gi anyway so it doesnt matter much, but a spec of like 5% and a tight hotspot will give it a subtle wax coating look) anyway then set reflection to any number, it doesnt matter cuz its controlled by a gradient anyway. Now to do the reflection click on the box with a T in it, it opens the texture editor. Change the layer type to gradient, and the input parameter to incidence angle. now click on the gradient bar to add a new band, drag it to the bottom and set it to something pretty low (like 10%). play with the settings until you get something you like. anyway what this does is it determines how reflective the surface is based on the angle to the camera, so parts of the car that are pointed towards you arent that reflective while parts that are pointed away from you are highly reflective. Also i think you should try a darker base colour for your car to get really cool results.

WChestnutt
04-24-2003, 09:09 PM
i've done the fresnel thing you said, thanks!!

i am going to try some different hdri's, as this ones reflection isn't what i want. i need a more clean reflection like the one shown in the link...

http://www.suurland.com/image_x.php?image=../images/gallery_stills_newbeetle_hdri.jpg

see how the reflection has really crisp, well defined edges!?, thats what i need!. surely this can be done in lightwave???!!!

Thanks for your help,

Will.

policarpo
04-24-2003, 11:59 PM
Originally posted by unknown limit
i've done the fresnel thing you said, thanks!!

i am going to try some different hdri's, as this ones reflection isn't what i want. i need a more clean reflection like the one shown in the link...

http://www.suurland.com/image_x.php?image=../images/gallery_stills_newbeetle_hdri.jpg

see how the reflection has really crisp, well defined edges!?, thats what i need!. surely this can be done in lightwave???!!!

Thanks for your help,

Will.

the higher-res your HDRI map, the better it will look. I was taking a low-tech approach with meni's car which ships with LightWave on this sample...about 12minutes on my ancient P3 1gHz.

my HDRI map on this particular one was only 190x120 pixels...therefore the blurry details.

http://www.policarpo.us/tutorials/menis_car.jpg

WChestnutt
04-25-2003, 10:10 AM
Hi,

i spent hours last night trying out different HDRIs but none of them came out looking anything near the quality of that beetle :thumbsdow

they were all hi-res maps, so on the test render you did, (thanks by the way) if it was a hi-res map it wouldn't be so blurry? because thats the kind of results i would like. (without thge blur of course)

Thanks,

Will

Cole
04-25-2003, 03:32 PM
Unknown limit:

If you want to email me your scene i'll take a look at it and see what might be wrong, email is cole@priest.com be sure you include your model file and the hdri image your using.

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