Jump to content
Jason

Cool mantra GI renders?

Recommended Posts

Dopeness! :lol: Very convincing amber.

I downloaded the dfx from the WinOSi site and tried screwing around with it a little bit. It seemed to me like irradiance by itself was not feasable speed-wise, and I couldn't get photon maps to work for some reason.

I was thinking how much easier it would be, if the GI controls were like Brazil's. Specifically having control over the number of bounces (with Brazil you can specify the number of secondary bounces your GI will have). Take the light-coming-through-the-window scenario. If the first bounce is not enough to sufficiently light up the room, you can turn up # of bounces instead of the global tint. This will take longer to render (render time goes up pretty much linearly with additional bounces) but it will give you much more realistic light behavior, and less noise than if you had simply jacked up the global tint. Is there some way of achieving the same effect in mantra? I haven't had any luck with the photon maps, and maybe that's the answer to my question?

Share this post


Link to post
Share on other sites

Hi Mark,

i setup an ambient occlusion scene using an HDRI image, and the lighting is great.  the problem is the environment from the HDRI is not reflected in the objects.  i had to add the HDRI map as an environment map to get reflections.  

im sure there is a better way to do it...   the material was just standard shiny metal.. but it does raytrace because it reflects other objects in the scene, but not the HDRI.

In my understanding, the Environment map in the VEX Global Illumination light shader is more Image Based Lighting than an environment reflection map. Hence, to have the HDR image as a reflection map, you have to set it up separately.

You have already discovered the Environment Map in the VEX Metal shader. Alternatively, you can do this easily with a Light & specify the HDR image in the "Reflection Map" parameter found under the Shading tab. Next, go to the "Viewing" tab, select "Projection" to Polar Panoramic & the resolution to 768x1024, assuming you're using a cross image.

To control the amount of reflection, adjust the Dimmer of the Light or the Specularity of your object as the higher the specular value is, the more reflective it will be.

I hope the above helps!

Cheers!

steven

Share this post


Link to post
Share on other sites

Hi all,

Here's another render.

curly_caustics4.jpg

Again, comments, criticism, suggestions, PayPal contributions :P welcome!

Cheers!

steven

Share this post


Link to post
Share on other sites

very nice steven...

what's that yellow thing in the upper left?

Share this post


Link to post
Share on other sites

Hi Steven,

your latest is a very nice render.

I'll try the HDRI technique as soon as i can. it sounds like a lot better control for lighting than just adjusting global tint which is what i was doing, cheers :)

Share this post


Link to post
Share on other sites

Hey guys,

arctor, the yellow thing in the upper left is part of the HDR image I projected on the background.

Thanks for the feedback! :)

Cheers!

steven

Share this post


Link to post
Share on other sites
very nice steven...

what's that yellow thing in the upper left?

very nice steven...

but whats that red thing in the middle?

Share this post


Link to post
Share on other sites
very nice steven...

what's that yellow thing in the upper left?

very nice steven...

but whats that red thing in the middle?

Good question Jason. Looks like an anamoly to me! :D Or like mark said, it looks like a dog. :lol:

Cheers!

steven

Share this post


Link to post
Share on other sites

hi all,

i followed your method Steven, and can get some good looking reflections. but when i add the GI shop network to the light, the reflections disappear. only 1 or the other can be rendered at a time.

so, i created 2 lights, one for reflections and one for the GI. this looks good, and being able to adjust them independently is especially good, but is this correct? there is no background projected, and i think the reflections come through the floor - that is they dont benefit from the ambient occlusion since they are on a seperate light.

anyway i will expriment some more, will be away from houdini for a few days though

:angry:

cheers :)

Share this post


Link to post
Share on other sites

After all the posts I thought I'll give the new GI tools a try. Just a wip/test image. I might spruce it up later on. Took about 20min to render with

fresnal+blurred reflections and full irradiance gi -128 samples.

cheers.

/jim

post-15-1071095607.jpg

Share this post


Link to post
Share on other sites

I haven't really followed this thread, but I'm going to comment on jimmyb's render for now.

Very nice there! The Houdini 6.1.x global illumination rendering capabilities are pretty damn nice.

The only thing in your render I don't like is the bright, and rather hard, specular highlight on the edge thing (?)

Share this post


Link to post
Share on other sites

nice

not sure where the red hitting the wall in the upper right is coming from...and the blue on the wall from the bookcase is a bit intense, but otherwise it's really nice...

Share this post


Link to post
Share on other sites

thanks:)

this is actually one frame from a sequence that i rendered. the "sun" is animated and you get to see the justification for most of it. i agree the blue is too intense too. actually, i really don't like the scene or the quality of the models i'm using. i should like to use some better models and a better environment now instead of these simple things. i think that its proved to me that the GI looks good enough/accurate enough to try to compose a real scene next.

anyone have any good free car models? like an old car or something. (studebaker style) we have plenty at work but i'm not allowed to use them, of course.

Share this post


Link to post
Share on other sites

I haven't fooled around with any GI stuff in awhile - maybe it's time to start again...

stu

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×