Z4R2: Understanding Lightcap, BPR shadows, and Matcaps. Confusion and Possible Bugs.

[Spyndel]

I’m trying to put BPR and the neat new Lightcap tool through the paces. All the stuff I’ve watched and read seem to indicate that Lightcap can allow you to completely disable the traditional scene light controls, and work through it exclusively, but I’m finding I’m getting a lot of strange results in terms of shadows not updating or behaving as expected. I was wondering if anyone had the time, could explain to me how much of what I’m encountering here are bugs, and how much is me just flailing at my keyboard without knowing what I’m doing.

So I’ve gone back, and broken down the BPR shadow experience into the most basic components, comparing the same functions with traditional lights, and then with lightcap, to try and make sense of it. Forgive my extensive illustration here, but I thought it would be easier in the long run, rather than explaining at length.

Each image represents a BPR render.

1. My loaded Shadow testing tool, in edit mode to work with BPR. Matcap White selected for easy shadow viewing. Traditional lighting controls. Default render settings, shadows enabled, BPR render.

As you can see, I can cast an accurate shadow from the light. Light intensity does not affect the shadow at all. Matcap shadow strength is controlled in the material palette. Understandably, light direction is not affected because matcap light is baked in, but shadow direction can be controlled.

2. Definite Bug: . If you disable all scene lighting, BPR render without shadows, then turn a light back on, the lighting does not update, and you will continue to render without shadows until you switch over to another render mode briefly (Best, flat, fast,) and then back. Checked ZB4, did not happen this way…shadows updated immediately upon turning the light back on.

3)Added another light, gave it shadow property to to see if I can get multiple shadows (Noticed that a second light doesn’t overexpose the Matcap materials like in ZB4 anymore…nice). Couldn’t get the second shadow to show up at first, until I realized that Light intensity does play a role with multiple shadows, so I had to turn up the second light’s intensity until it wasn’t being drowned out by the first light. Now I have multiple shadows.

So, in this situation, Shadow strength is controlled by both the Material shadow settings, AND the light intensity. And the floor shadows are controlled by another slider still. A bit confusing, but ok, at least I can understand and predict it now.

4)So now onto LightCap. As in the classroom video, I completely disable scene lights. Since LightCap is destructive to Matcaps, and I dont want to overwrite Matcap Cap White for this session, I paste over Matcap Chalk’s slot with Matcap White.

I assign one strong overhead light to Lightcap. Lightcap Shadows maxed. Material palette matcap shadows as normal (50). AS you can see, it updates the lighting, but there is no shadow. No combination or direction of Lightcap lights produce a shadow with the matcap. Updating the Matcap button in the material palette does nothing. (Tried switching render modes as with the previous bug, nothing)

5. So I select a standard material, to see how that works. Notice all the Matcaps in the picker are blank, and the standard materials are black. Mat picker does not acknowledge the light from Lightcap.

6. I chose Metal 1. The standard material behaves as expected. I can assign any number of lights, cast shadows from multiple directions.

7. I switch back to Matcap white. It casts a shadow now…but it’s Metal 1’s shadow. Notice how the light is coming from Lightcap’s preview direction, but the shadow is being cast from the direction of the preview in the old light menu, which reflects the last lighting I had given Metal 1.

8. Out of curiosity, I turn back on a light in the old Light menu, to see if maybe one of those lights have to be active to some degree in order to make shadows work. I get the hint of another shadow from the new light, but also some weird straight shadow that falls across half the tool that I have no idea where its coming from

9. I delete the Lightcap lights entirely ( I don’t see any other option to simply disable Lightcap). The material is now dark, and wont respond to lights even from the old light menu, like it was doing before. It wont respond until I repaste the white material into the slot, overwriting it.

So, I realize that Matcaps have lighting baked in, but they dont cast shadows unless you give them a casting light. If we’re rendering an object with Matcaps, do we need to switch to a standard material to establish scene lighting, and then back?

How much of this is me misunderstanding the concepts involved, and how much of this is stuff that is not functioning as expected? Anyone who takes the time to read this, and clue me in is much appreciated.

For the record, Win 7 64.

Thanks a bunch!

[Spyndel]

Anybody?

Ok, how about this then. I seem to frequently get my light direction inverted when using Lightcap. It seems to happen after Ive been messing around with background images. From then on , any light I add to Lightcap, the red light dot, and the light source seem to be on opposite sides of the sphere, and move in opposite direction…sort of like in the old light system where if you clicked on the light in the preview window, it would become a backlight.

Except, I dont know how I’m triggering it, can’t fix it once it happens, and I haven’t found any documentation indicating whether this is a bug or a feature I don’t know how to control.

Any help is much appreciated.

Thanks!

[Spyndel]

For what it’s worth, that shadow update glitch also seems to happen with Lightcap. If you’re lighting a scene with LightCap, and you turn down the Shadow Strength slider to every light to zero, then take a BPR render without shadows, BPR will no longer render shadows even if you turn the shadows back up, until you switch out to another render mode and back.

[marcus_civis]

Hi Scott,

I’ve not time to look closely at this now but I will just mention that BPR Shadows in 4R2 will only update if you move the model slighty between renders. The reason for this is that when you are adjusting other parameters the renders are much quick with the shadows cached. Apologies if you already know this.

http://www.pixologic.com/docs/index.php/Render_Improvements

[Spyndel]

Hi Scott,

I’ve not time to look closely at this now but I will just mention that BPR Shadows in 4R2 will only update if you move the model slighty between renders. The reason for this is that when you are adjusting other parameters the renders are much quick with the shadows cached. Apologies if you already know this.

http://www.pixologic.com/docs/index.php/Render_Improvements

Yes, I knew this, and it is a great feature…except when you’re trying to adjust the qualities of…shadows. If you make a change to a light that would affect the quality (or presence) of a shadow, they should update, yes? In the glitch I’m referring to, the shadows update in the next render when you disable shadows entirely, but do not update when you turn them back on, even when you move the model. Only switching out the render mode briefly brings them back.

It’s worth noting also, that casually moving the model is not something one tends to do once they’ve gotten that perfect camera position, even if they’ve got a marker down.

On a related point, Im not actually sure the Shadows slider in the Lightcap panel does anything. Even forcing refresh on the model by moving it slightly or switching render modes, doesnt appear to have any effect on the opacity of the shadow, which the description says it should. The only thing I’ve found that changes shadow opacity with BPR is the Material > Environment setting.

[Edit] ^ With further testing, it appears to be sort of like the Light Intensity situation in the old lighting menu. With a single light/shadow, it does nothing. With multiple shadow casting light sources, it does effect how dominant either of those shadows are.

I really welcome anyone else’s tests and observations here. Im sure most of this stuff Im just not understanding properly, but some of these things are slowing my attempts to work with the new tool.

[Zeddicus]

I’ve encountered every single issue you’ve mentioned multiple times. In fact, I just had a traditional light become a backlight and was unfixable. Shadows can sometimes be easy to fix like marcus mentioned, but a lot of the time I find the only way to get around a problem with them, as well as lightcaps, is to start over from scratch and pray it doesn’t happen again. I’m assuming these are all bugs, particularly because Z4R2 has set a new record for the number of times it’s crashed on me in one evening lol. I’m completely paranoid and incrementally saving projects like crazy now.

[jk1]

Paranoid is the right word. I really like the new system but it needs to be a lot more stable.

[system]

Am I correct in thinking that most of these issues are still present in R3? At any rate, I’ve noticed that trying out different lighting setups, moving back and forth between matcap, light cap, and traditional lighting, sooner or later gives you very odd results.