Author Topic: CoronaDecals playground!  (Read 3929 times)

2021-11-11, 03:03:31
Reply #45

marchik

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..to solve for example that limitation:
https://forum.corona-renderer.com/index.php?topic=34613.msg190985#msg190985

yes can use layered material, but decal is mutch more simple.

Decals are much simpler to use because they are separate object. By turning them to modifier, you basically would lose all the benefits, like ability to use decals on unlimited number of objects, an option to use separate decal material, freedom to independantly move decal in scene. I don't see what you would gain in return, other than you already can do with uvw map and layered material.

I just meant a Decal modifier (in addition to Decal object) that will turn any custom mesh into a decal instead of basic box/plane, which will be projected onto other objects along the normals of this custom mesh, and not a modifier on the base object, this gives the advantage of allowing you to use custom UV coordinates for the decal and increase the number of possible use cases.

Unlike layered material, this will allow you not to use the second channel of UV coordinates, quickly change the position of the decal in the viewport, and ofcourse apply it to several meshes at once

PS check the attachment

2021-11-11, 09:22:52
Reply #46

LorenzoS

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Quote
...... which will be projected onto other objects along the normals of this custom mesh
exactly what Decals lacks to be nearly perfect.

Quote
I just meant a Decal modifier (in addition to Decal object) that will turn any custom mesh into a decal instead of basic box/plane, which will be projected onto other objects along the normals of this custom mesh
to avoid introducing an additional Decal object, it may be sufficient to insert a checkbox in the current Decals to choose the projection mode of the UVW map applied to the mesh (the UVW map must not be applied to the decals)


2021-11-11, 10:42:14
Reply #47

romullus

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I just meant a Decal modifier (in addition to Decal object) that will turn any custom mesh into a decal instead of basic box/plane, which will be projected onto other objects along the normals of this custom mesh, and not a modifier on the base object, this gives the advantage of allowing you to use custom UV coordinates for the decal and increase the number of possible use cases.

Unlike layered material, this will allow you not to use the second channel of UV coordinates, quickly change the position of the decal in the viewport, and ofcourse apply it to several meshes at once

PS check the attachment

Oh, i see what you mean. Yeah, i agree, that's an interesting idea, but you have to keep in mind that we'd need to deal with projection cage here. In your specific example, it is esentially still a planar projection, but with more complicated meshes you may easily end up with unexpected results, where projection would be stretching, or projecting onto itself. Such decals would be nowhere near as fail-proof as they are now and we may end up with situation, where support have to deal with bunch of false bug reports, "my UVs are perfect, so why my decals are fucked up?" - not everyone knows the difference between UVs and projection, as you can see from this topic alone. Look, i don't want to speak too much against your proposal, i already have been accused in advocating for Corona team too much, i think it's an interesting idea and it's worth to be considered, but it might be not as simple as it seems from a first look. Anyway, it's for the team to decide if it's worth the hassle.

BTW, if you go as far as detaching polygons from target mesh, you already have a decal, you just need to add push modifier to it with small positive value to avoid overlapping, assign decal material with opacity, maybe throw in Corona ray switch material to disable shadowing and you have perfect decal. This technique is nothing new, it has been used for ages in CGI. It might be even slightly faster to render than CoronaDecal, because there's no need for layered material anymore.
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2021-11-11, 18:46:08
Reply #48

marchik

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BTW, if you go as far as detaching polygons from target mesh, you already have a decal, you just need to add push modifier to it with small positive value to avoid overlapping, assign decal material with opacity, maybe throw in Corona ray switch material to disable shadowing and you have perfect decal. This technique is nothing new, it has been used for ages in CGI. It might be even slightly faster to render than CoronaDecal, because there's no need for layered material anymore.

yeah, I use this approach of course (otherwise where would I get these screenshots:D) the only thing missing is 2 displacements interactions, including negative values for the decal, that's why I made  a request for decals in the "most wanted feature" topic a long time ago, and now they are finally here, just a little bit left.

And let's be honest, decals in their current form are also not absolutely fail-proof for a beginner who has not encountered them, I am personally ready to prepare a post for the Corona blog on how to straighten UVs! :D


2021-11-11, 19:08:20
Reply #49

LorenzoS

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I am sending this post not to insist but only to clarify my proposal if it is feasible.

The result I would like to obtain is the one done with the layered material, the Decal should have an option that constrains the projection to the unwrap map applied to the cylinder.

2021-11-11, 23:39:14
Reply #50

Dalton Watts

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I'll put the suggestions I've made on Daily Builds Discussion here since they're (mostly) related to Corona Decals:

- Will Corona Decal Order function be implemented?
Just like how Vray 5 decal order works where higher numbers mean top decals and vice versa.

- Added the option to drop bitmaps from Windows Explorer directly into our material slots
This function is great but although not entirely Corona Decal related, another improvement would be also letting you drag and drop any bitmap from Windows Explorer to the CoronaDecal's mask source map slot (while automatically assigning the mask source to map). I reckon this could be much more complicated to implement as I suspect this could be more an Autodesk issue but IMHO it would be much better than drag and drop to slate material editor and then drag to mask source map slot. 1 step vs 2 steps.

This last suggestion could be useful for any Corona Object that has an option for a map to be loaded (CFractal Texmap for example).

« Last Edit: 2021-11-11, 23:55:38 by Dalton Watts »

2021-11-22, 15:36:49
Reply #51

aaouviz

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How about an option to use hidden decals?

I'm using them as road markings, but they're quickly becoming a bit busy in my scene and making selection of other objects a bit harder. I'd like to hide them but not lose their functionality.

Thanks :)

2021-11-24, 11:01:16
Reply #52

Rhodesy

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Just to confirm I'm doing it right. The only way currently to get a decal that doesnt have displacement placed on top of a displaced material is to add a solid white map to the displacement channel of the decal? Seems to be the case even when the replace base disp checkbox is ticked. If so is it possible to have Corona do that automatically internally without having to add the map manually? Also means that the light material used in the quick example file must inherit the displacement from the base layer as there is no option to add a displacement map in to the light material.   

Sorry if I've overlooked this in the thread previously.

Cheers