IBL reflections on a model

[Eric2575]

I'm playing with IBL and placing an object in a scene with reflection ala Stian's tutorial. First I render out the background image which I then use as a camera rotoscope. Next the ground is set to Front Projection "on" in order to receive shadows, then I import a sphere with reflectivity set to about 35%. That's when I run into problems. The sphere, although it is not set to Font Projection "on", has a transparent image of the rotoscope on it. It's supposed to have the reflection of the environment sphere on it, not the rotoscope. What am I missing here? When I remove the rotoscope from the camera, the sphere has the correct reflections, but off course the ground is blank without the projected rotoscope.

 

In the pic you can see that the camera rotoscope is covering the ball, although very transparently. Since the sphere's Front Projections is set to "off", the camera's rotoscope should not interact with the sphere at all, right? I hope someone has a simple explanation for me.

 

Thanks

 

-E

[Eric2575]

Here's a better pic. The sphere looks transparent, but it isn't. That's the Camera rotoscope acting on the sphere.

[agep]

Not sure if it helps, but select your Ground plane, within Options set 'Cast Reflection' to OFF, let the sphere cast the reflections of the ground

[NancyGormezano]

The sphere, although it is not set to Font Projection "on", has a transparent image of the rotoscope on it. It's supposed to have the reflection of the environment sphere on it, not the rotoscope. What am I missing here? When I remove the rotoscope from the camera, the sphere has the correct reflections, but off course the ground is blank without the projected rotoscope.

 

Do you have your environment sphere model active? And is the image on it mapped correctly?

 

I am a little confused as to what I am looking at in your images - it looks to me like the background is the camera rotoscope (projected onto ground plane, and showing in the background, as there is no actual model there) ?

[Eric2575]

The environment model is active and mapped correctly - as far as I can tell. When I do the final render, the E-sphere is active, the reflective sphere is active and the ground is active. Lighting is IBL with one sun light for shadows. The ground is set to Front projection "on". The rotoscope and projection map are lit so they appear uniform upon render. I will post two pics, one with the camera roto, the other without. That should help explain the problem a bit better.

 

Stian, Cast Reflections on or off on the ground plane does not make a difference.

 

Ok, so here are the pics - all settings are the same except the first pic has the camera rotoscope and the second one does not. Note that the environment sphere is active and mapped correctly as can be seen by the reflections in the red sphere. So how do I get the projection on the ground as in the first pic with the proper reflection on the sphere as in the second pic?

[Eric2575]

For some reason I can't seem to use the edit function on the board anymore. The pictures posted reversed - the first picture does not have the camera rotoscope, while the second one does. There are no other differences and both have an active projection mapped environment sphere surrounding the scene.

[Eric2575]

Here is one more pic with a simple slab model set at 35% reflectivity. The slab shows the same characteristics as the sphere, so the problem does not lie with the models in the scene.

[Eric2575]

Wireframe to show active environment sphere, reflective sphere, slab, and ground plane.

[Eric2575]

Here is the same scene without the camera rotoscope.

[Eric2575]

I have also tried the usual tricks like saving, shutting down AM and restarting. It must be something simple I am missing.

[Eric2575]

This render is with a stock photo as a camera rotoscope with no ground plane. The Environment sphere is still active. Same funky rotoscope overlay on the reflective sphere!

[NancyGormezano]

hmmmm...very strange - what seems also funny to me is that your lighting on background buildings changed (in first post with just red sphere) when turning camera roto on/off - that shouldn't happen. I am assuming those background buildings are the environ map on the dome.

 

I cannot duplicate your results - I have a 100% reflective sphere, floating above ground, dome with env map, front projected ground plane, camera roto. 1 sun light, IBL (color=white, no occlusion) - and it looks fine to me

 

this is screen capture

[Eric2575]

Ok, finally something that may narrow down the problem - I deactivated the environment sphere in this render. The only item is the reflective sphere and the stock photo used as a camera rotoscope. Now I have no rotoscope overlay, but I don't have the environment reflection either.

[NancyGormezano]

Same funky rotoscope overlay on the reflective sphere!

 

do you have another camera roto that is set to be ON TOP and is partially transparent?

 

My camera roto is NOT on top.

[Eric2575]

Nancy:

 

couple of questions:

 

Are you using a projection map material on the dome or an environment map material?

 

What are your sphere settings?

[Eric2575]

There is no other rotoscope and it is not set "on top"

[NancyGormezano]

Nancy:

 

couple of questions:

 

Are you using a projection map material on the dome or an environment map material?

 

What are your sphere settings?

 

environment map on dome, sphere is 100% reflective

 

ground is front projected ON

[Eric2575]

I knew it had to be something simple - I narrowed it down to the environment sphere by ny last experiment eliminating it from the scene and thereby losing the rotoscope overlay. Now I looked at it again and saw that the environment sphere had "Front Projection Target" turned on. Turning that off fixed the problem.

 

Thank you Nancy and Stian for looking into this with me. Much appreciated

[NancyGormezano]

bueno!

[ypoissant]

Don't forget the gamma correction.

[Eric2575]

Now I'm having trouble matching the ground plane image with the background. This is very evident in the last image Yves posted. The ground is lighter than the background. If I render the background image without any gamma setting, the render is way too dark. If I render with a gamma of 1.5 or 2, the background image looks ok, but when I use it as a rotoscope, the part that projects onto the ground plane gets washed out.

 

Stian, any chance you could revisit your IBL tut and get a bit more detailed with it?

[ypoissant]

I guess your groung plane texture is coming from a photograph. In that case, you need to reverse gamma correct the groung plane texture before using it for render. That is apply a gamma 0.45 to the ground plane texture in Photoshop.

[agep]

Now I'm having trouble matching the ground plane image with the background

First, makes sure that your ground plane don't have any Ambiance Intensity set to it (some of the Primitives from the Library use to have 20% set to them). Other than that I usually Increase or Decrease the Ambiance Intensity within the Choreography options to make the Environment sphere and Ground plane match

[Eric2575]

When I get home tonight I will start with a new test project and Dosch Designs HDRI images to see where the trouble is. I will post every step I take and the resultant renders. This should be fun and informative.

 

Yves, the ground plane texture is coming from the camera rotoscope that was made by rendering out a Dosch HDRI image applied to an environment dome via a projection map. Ok, say that ten times fast