Rookie question in lighting: Do I have to make sure the pixel values don't go beyond 1 when the light is very bright to avoid clipping? Is there a case where the pixel value may go beyond 1? Below is a human body on which a very bright sun is shining, I had to increase it's exposure so I can get brighter global illumination, but I ended up with clipping.

it says in the docs: "Scatter channel to read from the volume object. This acts as a multiplier on the scatter color, to texture the color of the volume." https://docs.arnoldrenderer.com/display/A5AFMUG/Standard+Volume What multiplication is that? 1 (colour white) * density? There is a big mess in the bottom of the cloud so I'd like to know what is the formula used? what's multiplied by what? If my volume is 9 times denser and the colour is 1 (white), does it mean the denser the brighter? I've included comparison (top: empty channel, bottom: channel is density)

I have attached files. I just can't get any self-shadows on volume. I've rendered the shadow matte testing on a polygonal geometry and it works like a charm, but for the volume (in this case a cloud) I can't get anything at all, using both: - just shadow matte AOV - duplicated volume with shadow matte material Everything works fine for polygons, nothing whatsoever works for volumes when it comes to shadow matte / pass. Am I doing something wrong? I need the self shadows of the volume. The volume (cloud) is from Disney: https://www.disneyanimation.com/data-sets/?drawer=/resources/clouds/ And here are the houdini hip files shadow_matte_polygonal_geometry_works.hiplcshadow_matte_polygonal_geometry_works.hiplc floating.bgeo.sc shadow_matte_volume_does_not_work.hiplc shadow_matte_polygonal_geometry_works.hiplc

Does Arnold now support packed primitives in scattering or do I have to use the old instancing method?

The Disney Cloud dataset includes multiple resolution versions with the highest being almost 1,5 billion voxels (2.8 GB file size). Does this stuff get used like this, with so many voxels? Here is the link: https://disneyanimation.com/resources/clouds/ Can someone shed some light on the resolution range for cloud in production (close up, mid, background)?

I attach the hipfile of a closed interior scene, just a window letting the light in. I have a VERY HARD TIME lighting the REST of the scene, the one that's not close to the window is unrealistically dark. Am I doing something wrong? I've tried with: Dome light HDRI + Sun Exposure 10 + Portal 1, exposure 22! + Portal 2, exposure 21! + Area light exposure 8 The light doesn't go further, the rest of the scene is dark and the window area is too bright. If I add a point light inside to cheat, I get the bright spots on the ceiling, the floor and nearby walls/objects. If I add an area light the rear will be darker than the front, if I make it double sided, the edges will be darker. Here is the free scene I'm using (file sop): https://www.turbosquid.com/3d-models/3d-design-kitchen-gray-model-1616267 Perhaps, a more direct question: how would you light it? lighting_interior.hiplc

For an old scene, I'm switching to Arnold, how do I add the Arnold tab in the parameters window? is there something like the "Add OBJ Parameters" in Redshift menu:

Thanks a lot for the prompt reply. I will check it. Perhaps I've formulated in a confusing way, let me try it again in 4 words: HDRI or Plain colour?

I'm interested in studio practices: are HDRIs used in lighting clouds, or just plain colour? I've tried both, but the HDRI comes with a the ground which makes the bottom of the cloud quite dark, increasing the exposure makes the top part unnecessarily brighter. HDRI does give a "richer" lighting though. What do you use for lighting clouds in Env/dome light?

I'm supposed to "connect a physical_sky to the color attribute of a skydome_light" as per autodesk documentation, but there is no physical sky. And if I'm to connect a distant light to the color how is that connected like what parameter to copy. I'm trying to adjust the sun elevation (day vs sunset).

I attach file where I use font to display parameters. Both are float, but one shows as the exact number I've entered, and the other is misbehaving. For scattering phase I've entered -0.7 but it's displaying -0.69999999999999996 This is not helping visualise the parameters used. I just need my -0.7 Other than wondering why one float is ok and the other is not, how do I get the font to read and display -0.7 correctly? truncate_float_in_font.hiplc

I attach a file where I need to render 10 times, each time with a different smoke density in the shader: 1, 2, 3...,10. All the wedge rop stuff I found was about automating the asset generation, exposrting vdbs, but I do not want to export vdbs, I just want to render the very same only one asset each time with a different value for the smoke density. Any idea? multiple_renders.hiplc

I'm trying to use vel in the control field. Normally I would go inside the gas Disturb, find the control field, change it from float to vector and add a length node. But when I tried in Houdini 19.0.622 I found a mismatch between the parameter at Gas Disturb level (named control field) and the parameter inside the vop (named control, and not control field) Am I missing something? why is it named "control field" in the parameter interface of Gas Disturb, and named "control" in the vop? control_field_lengthg.jpg is from Houdini 17 showing how it used to be done, and the other two images are from H19.0.622

Attached hip file, I'd like to mask the top part of the vdb sphere using the box. this should create a mask that I can use in Volume vop to add noise vdb_mask.hiplc

Let me asked differently as well: one geo node for all grids and materials or one geo node for each material? What is best practice / what would you do? Plenty of surfaces (some grids and boxes) each has a material (Megascans surface). Not all surfaces have the same displacement scale, so the displacement scale I need for each megascans surface will be different, because the surfaces are different. Fair enough, I can change the value for each in the material displacement scale. But there is under obj node a displacement scale as well. Would you: (1) have all walls and floors and ceilings inside one obj node (e.g. geo1) and tweak the displcement scale in the material node for each material or (2) have an obj node for each material e.g. floor and ceiling share the same material, so floor and ceiling will be both inside a geo node, and other geo nodes are driven by materials, 1 geo node <-> 1 material.