another day another question… i promise it won't be everyday

in one of my models i have a panel that i want to be a light. so i followed the light instancing tutorial precisely multiple times, but my results differ from theirs… im considering just using a normal light not instancing, bu the geometry shape is irregular id like to solve this problem..

i created a shop light shader, i assigned this to my ‘light’ geometry by choosing point instancing. i then created a light, which under the render tab i set to use point instancing and selected the ‘light’ geometry. according to the video i should be all set.

the video implies that the light will not be used, that the points on the ‘light’ geometry will be instead, and they will use the shop light shader. so what i concluded from the video is the light that you create is partly redundant, like a GI light… not used directly but needs to be included in the scene.

anyway i found out that the light does affect the scene - the geometry is actually emitting light - but from the position of the actual light - not from where the geometry is… strange indeed !! (i can tell its the geometry emitting the light, because adding a shadow shader to the shader SOP makes it render very slowly indeed… like an area light.. so its working just not in the right place)

i dont understand what is happening..

in the help file is says that any transforms applied to the light will also be applied to the instanced points. i tried creating a light, and the only transform was rotating to the correct direction… same problem., my light is emitted from the place of the light not the instanced geometry. so, i dont think the transforms in the light is causing the problem.

perhaps i need to move my light into place, then somehow reset the transforms to null, then instance it? i dont know how to do this, or even if i need to…

i will try again with a new scene and basic geometry, but if anyone can see what im doing wrong that would help a lot

ugh it turned into a thesis not a question. thanks for reading if you got this far! hopefully in the future other newbies can benefit from these posts and replies too if they use the search function.

I tested out what the help card says and it seems right to me. Both transforms are being used. It helped me to parent the instancing object as a child of your light. This should show you the final position of light instancing geometry without guessing.

Another thing I found useful was to use a Null object as the container of my light instancing geometry so that I could leave its display on to see where it is but have it not render.

thanks Edward, the null sop tip is handy. like you, i just made a basic scene and tried this and it worked perfectly … heh, didnt have to move the light at all. so something is wrong with my main scene. i'll export the geometry to a new file and try again

Hi again, just wondering if anyone can explain the using a null as a container object. i assumed Edward meant make the last SOP in the heirachy a null - but this doesnt hide the object from the renderer. if its in the video or PDF's pls say so, i have looked at a lot of the material but not everything.

also i want to make the object self illuminated.. i made the diffuse, specular and ambient all white.. that seems ok.

but, anyway to easily add a glow? i cant see it anywhere.. do i need to colour key this in post or is there a better way? i thought there might be a glow VOP or similar…

thanks!
Mark