Messages

1

[Max] I need help! / Re: Corona Proxy internal pivot point

« on: 2024-03-14, 12:13:16 »

ok, that worked! Bit of a pain but it does work.

Thanks.

2

[Max] I need help! / Corona Proxy internal pivot point

« on: 2024-03-14, 11:04:40 »

I have created a single proxy from a bunch of geometry, when I create the proxy the version created in-scene seems fine, the pivot point is at the original (model on the left below)

However when I load the .cgeo file in to a new corona proxy object it appears to have been created in Y up and the pivot seems to be in an arbitrary position.

How is this [internal] pivot created and stored?

If I'm not mistaken, V-Ray will create a single object proxy as pivot at origin and Z up, so I Proxy created in-scene will have the same pivot point as one created by making a new Proxy object and loading the vrmesh file, this is what I was expecting

Obviously, for now, I can use the one created in-scene, copy across to my new scene and place, but I'm concerned that changes to the bounds of the object will cause a shift in this internal origin, if it's updated, and hence a shift in the referenced geometry in my target scene.

3

[Max] I need help! / Re: Thin glass - no light passing through at lancing angles.

« on: 2023-12-03, 22:44:19 »

yes it was the geo that was the issue, specifically I had edited the glass to that it was a single face rather than a water-tight, shelled plane. in the problematic areas the direction of the base spline on the railclone object meant we were seeing the back face of the glass. That's fine, I usually would shell glass anyway but in this case I have a bump making the glass ridged and didn't want to overcomplicate the look of this by having two ridged surfaces. In the end I added a front/back map so the bump only rendered on the face closest to the camera.

It does make me wonder though - if we use a thin glass, with shelled geometry, don't we effectively end up doubling up reflection? - i.e it's like having a double glazed window rather than a single pane of glass. Obviously this might be desirable in some cases, but in this case I'm trying to create a single glazed partition (or at least simplify the rendering/look to the greatest degree possible.

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[Max] I need help! / Thin glass - no light passing through at lancing angles.

« on: 2023-12-01, 10:30:36 »

I have a glazed partition with a thin glass material , the mesh is arrayed with railclone and the segment itself is just a single face - no thickness.

At glancing angles (less than about 30 degrees) there appears to be no light passing through the glass.

Is the single face approach correct when using thin glass material? Any ideas what's causing this problem?

5

[Max] I need help! / Re: object attributes in Corona

« on: 2023-11-01, 17:49:44 »

Maybe you are just not aware of the fact that you need to restart interactive rendering when changing object properties to see the result. Because your example just works here :)

haha thanks, yes I realised this shortly after posting.

OSL named attribute

Ok, I stand corrected, it does work! I think it was the same issue, I wasn't refreshing the interactive render.

CoronaMutimap

Yeah I can't see how this works. Would be great if it did as you have the batch texture import there

6

[Max] General Discussion / Re: ACES Color Space

« on: 2023-10-31, 23:25:05 »

When I've used it previously it's been too lightmix, control certain elements: reflections/shadows etc individually, and comp in photographic elements.

7

[Max] I need help! / object attributes in Corona

« on: 2023-10-31, 18:32:01 »

I'm trying to create a master material for a range of fabrics. I've used this method before with Vray, but something isn't playing nicely now. My method then was to use a custom user attribute to pass on an index to an OSL 1ofN node which picks the appropriate map and passes it on to the material.

I just found this in the OSL documentation:

'OSL also allows the generic getattribute() function to get a named attribute from the scene. It is up to the renderer executing the OSL code to populate these named attributes, which means it is outside the control of the OSL Map itself to guarantee whether these attributes are defined.'

Does this mean that Corona can't get object attributes for shader level functions?

Any alternative mathods anyone would like to suggest? I am trying to use object ID as an alternative via a CoronaMultiMap, but it doesn't seem to be working currently.

8

[Max] General Discussion / Re: ACES Color Space

« on: 2023-10-19, 16:38:12 »

reverse the transform: srgb display to linsrgb, expose with multiplying linear data, go back to acesot (aces' srgb display odt). fnord had ocio plugin for ps. or make some luts for -1EV, +0.5EV etc. or maybe even curves presets.

I think I'm with you, you're saying to get (for example) an exposure adjustment to work correctly in photoshop, you have to transform back to linear, as an image with baked ACESOT LuT will not be linear!?

9

[Max] General Discussion / Re: ACES Color Space

« on: 2023-10-13, 10:51:55 »

I noticed the ACES OT option kills dynamic range in a 16bit file. Does anyone have it as a LUT so it can be placed at the top of a stack in photoshop instead?

10

[Max] Daily Builds / Re: Cryptomatte playground!

« on: 2023-09-29, 10:26:34 »

Any plans to add cryptomatte by material to the options?

I used this all the time in VRay and I'm struggling without it!

11

[Max] I need help! / Turn off max displacment but keep Corona displacment

« on: 2023-09-22, 10:13:37 »

Not sure if this is an option, I can't find anything in the setting. I'm fairly new migrating back to Corona from VRay after a while with the latter.

I have a few objects with displacment textures, when I have a Corona displacment modifier on top, they work fine, taking the map from the material. When I turn off this modifier it interprets the displacment via the Max scene units (meters in this case, so the object blows up)

I VRay there was an option to interpret the displacment via a set figure (1x scene unit by default I think) which could be turned off so that displacment only happened if a Displacment modifier was present and turned on.

Is there similar in Corona?

The reason I ask is I'm trying to debug some displcment that is looking wrong on an object, so wanted to just see with/without by flicking the modifier on and off.

12

[Max] General Discussion / Coming back to Corona

« on: 2023-07-26, 13:49:20 »

Hi guys, I've used Corona before, but have been using Vray for the last few years, in which time I think the merger/buyout happened. I guess the last version I used was probably 5? Would have been at the start of 2018 and I can't remember whether we were on the latest version by then.

I've landed a new job and the studio uses Corona, so wondered if anyone has any thoughts on differences between the two. I know these are probably few and far between since the merger, but interested to hear what adjustments you made to your workflow since adopting Corona.

I just finished a project using VRScenes as a kind of Xref, worked well, but this seems like one notable omission (maybe I'm wrong here, I know there's the .cdo filetype, can this just be loaded through a Corona Proxy object?)

13

Work in Progress/Tests / Re: Camera Tracking Test

« on: 2021-10-26, 10:56:36 »

The car isn't reflecting in the floor.

It is, from 30s, probably not quite correctly but it's definitely there.

14

[Max] I need help! / Re: Settings for animation

« on: 2018-08-03, 11:36:14 »

Cool, thanks for the help. And agreed, it's a stupid lighting setup that caused me no end of hassle, not helped by someone moving the HDRI files on our server!

If displacement fits into your RAM

What do you mean by this? Is it related to the pixel size of the map? like 1024 x 1024 px?

15

[Max] I need help! / Re: Settings for animation

« on: 2018-08-02, 18:44:54 »

Hi, I am sure there is a way to render both flicker-free, but first we will need to understand more about the scene itself:

Glasses:
1) Are you using path tracing only, or path tracing + uhd cache? (performance tab) I would suggest using path tracing only in this case.
2) Are you using denoising here? I would suggest switching it off, as it can produce different results for different frames, especially with not enough passes.
3) How many passes per frame is this?
4) What kind of lighting are you using? Corona's Sun+Sky? HDRI? The idea is to understand what is this bright highlight in the glass material.

Wall:
This is definitely displacement being re-calculated for each frame. For animations with moving cameras, the solution is to:
1) Use bump maps for fine details, and displacement only to define the overall structure of the material (e.g. bricks)
2) Switch from screen-space to world-space displacement in the performance tab (this will prevent flickering, but displacement will be calculated for the whole object, even if its outside of the camera frustum, so more RAM may be required.
3) Adjust the displacement size in the performance tab to find good balance between quality and RAM usage (lower values mean higher quality displacement, but more RAM usage)

In case of the glasses, you can try the following advice:
https://forum.corona-renderer.com/index.php?topic=19065.msg119271#msg119271
https://forum.corona-renderer.com/index.php?topic=14429.msg101324#msg101324
https://forum.corona-renderer.com/index.php/topic,16522.msg104046.html#msg104046
https://forum.corona-renderer.com/index.php?topic=19628.msg122645#msg122645

Glasses:
1) yep PT&PT
2)yep denoising
3) I'm not sure, I set the noise limit at about 6% from memory
4) I think that was Corona Sun& Sky but the person who set that file up had a weird mix of HDRI/Sky in a few of them, I did strip that out on most of them, I think this one too.

Wall:

Ok thanks, I'm moving away from using displacement on animations where possible because of render times but that's all good to know.

Cheers! I'll check those threads out tomorrow.