Hello.

I am doing a project.

A shot requires that my actress is in a Matrixesque “white light” environment (the whole scene is surrounded with uniform white light). Just at the moment I am struggling with the shader to add to the one scene element except her, who is being comped in later.

I have a shot of her from the perspective of the element (a perfectly reflective sphere which is to shatter onto an invisible surface in front of her). I have spherized it (it was green screen so is white now), and it is an image sequence, and I would normally plug this into an envball node into the reflected colour of a shader in Maya (NB: I am switching from learning Maya to Houdini).

I've used a Mantra surface material and am looking at the reflection section but am not quite sure how to proceed.

Advice would be awesome. On this and generally the whole sequence.

One other thing… I stuck in an environment light with ray-traced shadows. Does environment light come from all directions equally or is the icon misleading?

Thanks in advance.

Hi,
From your post can we safely assume you have a 3d object and want a HDR reflected on the suface of your 3d element.

One other thing… I stuck in an environment light with ray-traced shadows. Does environment light come from all directions equally or is the icon misleading?

The simple test would be to add a env light and render a teapot on a grid , make sure you add a HDRI map to the env light and throw a chrome shader on the teapot

Rob

thanks

cool will try that as soon as the shattering has finished simulating.

would it be a good idea to use AO as well? or just ray trace shadows on the env light?

5DN
thanks

cool will try that as soon as the shattering has finished simulating.

would it be a good idea to use AO as well? or just ray trace shadows on the env light?

Hi you get AO for free with the env light

Rob

is there a node to turn a square video shot of a chrome ball or even a spherized image sequence into a HDR image map?

You should be looking to PTgui and Nuke to do that

Rob

thanks for your help

done Nuke mapping of sphere to latlong exr. Added to envlight enviromap but during render the object comes out pink all the time. I can see the map in the background of the scene view. is this a Mantra issue?

Pink > means there's no map. Check your path and file format

Rob

even though I can see in the scene?

CUsers/5/Documents/zebraxing temp/rzlatlong/RAZlatlong.exr

this is path

colourspace is linear?

console is saying "mantra: Unable to load texture 'CUsers/5/Documents/zebraxing temp/rzlatlong/RAZlatlong.exr'"

don't understand though because i can see it in the scene viewer?

does it have to be .hdr

??

Thanks Rob BTW for your help.

Rob I think I worked it out. I had compression on the exr in Nuke. Trying now but Nuking will take a while.

5DN
Rob I think I worked it out. I had compression on the exr in Nuke. Trying now but Nuking will take a while.

Nope. hehe. I reckon its because I'm trying to fake an HDR image rather than actually using one? does that make sense. My original file is just a spherized HD image seq.

ironically its good because I will do proper HDR imaging in a chrome ball now for my shoot day, rather than use crap faked spherized HD video.

that make sense?

5DN
colourspace is linear?

console is saying "mantra: Unable to load texture 'CUsers/5/Documents/zebraxing temp/rzlatlong/RAZlatlong.exr'"

don't understand though because i can see it in the scene viewer?

Its failing because your reading in $F in your format change the file to be RAZlatlong.exr

Rob

5DN

5DN
Rob I think I worked it out. I had compression on the exr in Nuke. Trying now but Nuking will take a while.

Nope. hehe. I reckon its because I'm trying to fake an HDR image rather than actually using one? does that make sense. My original file is just a spherized HD image seq.

ironically its good because I will do proper HDR imaging in a chrome ball now for my shoot day, rather than use crap faked spherized HD video.

that make sense?

No its not failing due to any of that. Its due to an error 50 . That means you , sitting 50inches away from the screen.

Rob

silly me. i've reset!

but i have a question if poss Rob. how do I plug a spherical image into the reflected colour of a material, as this is what i need and not an env light?

ta

Have you not read the docs on env maps ? . I always use lat long maps. Edit them in Photoshop / Nuke.

Rob

Dear Rob,

Please tell me if I have no hope but I am absolutely at my wits end with this. Before I RBD simed the fractured sphere and exported as ABC to Maya, then I plugged spherized image sequence (instead of image of chrome sphere shot, as I had done in previous project) into an envball node which was plugged into the reflected colour of a phong of a material and hey presto it worked. Then I wanted to change the sim and the ABC export refused to export the geometry (although the file was many GBs big as before). Deciding to get around this by learning to do the whole shot in Houdini (as I have been planning to entirely learn Houdini), I have come across the current problem.

Not wanting to repetitively bother you, I have spent much of the last few days trying to understand what I have done wrong or have not done right.

Cannot find much documentation on env maps.

Can you help please?

Yours “going crazy!”,

5DN.