Shadow plane visibility

I am having issue with undesirable results when using a plane as a shadow catcher.

When I take a look at the dragon example scene, the Plane (Character) object is displaying the shadow of the dragon, with no visible edges where the plane ends. I’m playing it as an AR scene in We3D. This is the behaviour I want.

My shadow planes always have a visible edge. I have replicated the settings from the dragon scene, even copied the light over, but I still get visible edges.

What are the most important considerations when creating a shadow plane? Do you have any tips?

Thanks,
D

Hi Darren,

Glad to see you’re experimenting with some more advanced features!

So there are 2 methods to get an edge free shadow plane.

The first one requires you to set the blending mode of the shadow plane to modulate 2x. Think of it as the multiply blending mode in an image editing software. All the white pixels will be invisible while the darker ones will be visible (@pierre will be able to confirm the exact behavior).

That being said, the shadow plane is lit by the lights in your scene. To get rid of the edges, make sure you don’t have an image based light texture in your light. Then check the intensity of the lights, they should have a neutral effect on the plane. In the work view, you can use the background checker as a tool to see if the edges are truly invisible.

The second method is a lot easier, you can simply place a radial gradient texture (white to black) in the opacity channel of the plane. Then activate the translucency of the material.

This method is bullet proof however the shadows can only be as visible as the plane.

Could you upload your project? I could make the adjustment for you.

Cheers!

With multiply, white (one) preserve the color of the background (thats the video feed in the case of AR) and black (zero) will turn it to black.

Hi Guys,
Thanks for the tips.

I am still finding it hard to control the plane, even when I have made some of the changes you suggest.

I do have an ibl node, but I tried taking that out and didn’t see a difference. Also with the radial gardient in the opacity slot seems hard to control fully.

You can check out my project, link below. I’ve tried a few different techniques as you can see. I am getting the best results using the prebaked shadows (loaded into the opacity slot), and having the shadow catching item on TranslucentInvAlpha blend mode.

One if the tables, only uses a radial gradient as suggested.

These solutions seem to work fine for now. I’d be interested to see if you could achieve a clean result using only the scene lighting and the radial gradient.

Your file “AR-MENU_ALL_v10.zip - 18.3 MB” is ready for download: https://share.theimagefaculty.com/_hZJhFfMBIZUV9R

Thanks D.

Hi Darren,

I took at look at your scene. It seems the issue with the edge was partly due to its diffuse color. It was in the middle range. I’m preparing the modified scene for you.

Cool download page by the way :wink:

If you shift the color of the diffuse on the plane towards white you can get to an acceptable result. But since you’re only using one light source the effect isn’t perfect on all edges. One area is further away from the light so the edge becomes visible.

What I did was to invert your radial gradient and removed the modulate flag.

This way the plane progressively disappears towards the edges.

The positive aspect of using this method is that the shadows are dynamic and can move if you rotate the models around.

The downside is that the area at the center of the plane will be affected by the scene lights so the shadows won’t be super dark. You can still use it to your advantage for indoor scenes as the shadows appear compensated by the global illumination.

This is the method used in the video bellow:

The project file: https://nas.talansoft.com/sharing/4gkPrmpa7

Hi Chaps,
Thanks again for the advise. You made it seem so easy :slightly_smiling_face:

I actually like the fact that the centre of the plane (and therefore) the shadow receives light. As you say, it stops them from getting too dark and heavy.

Cheers,
D

You’re welcome!

Valkyrie’s purpose is to allow users to achieve results quickly so the most simple solution is often the best one.

Let us know if you have other questions. We’re constantly improving the software so we’d also appreciate some feedback on what can be improved.

Cheers

Hi Louis,
I have a couple of feedback points I can mention.

As a new user it’s always great to see tutorials, and I personally prefer video tutorials I would say at the moment, I can see there is a lot of functionality in the actions and events, and showing the potential of these as much as possible would be helpful.

A specific function: it would be great to have the option to switch off the image preview that pops up when you hover over an image listed in the library. At the moment generating this preview can create a pause, which comes off as the program freezing.

Just my thoughts for now.

Thanks,
D

1 Like

Thanks for the feedback, the next release will have the automatic image preview disabled. To see the preview the user will have to press a hotkey while hovering on the bitmap.

We have plans to produce more advanced video tutorials. You can subscribe to our youtube channel for updates.

Cheers