Render25 branch bugs report

Bug report is not allowed for branches so in the last months I’ve directly reported render25 branch bugs to brecht via email.
Now we know brecht is leaving Blender Foundation and the renderer refactoring plan he started working on last months will (hopefully… !) gain attention of other devs in the next months.

I’ve opened this thread as an users reminder to track render25 bugs in the meantime, collecting them for the moment when it will be possible to report bugs to tracker directly.
If you’ve found bugs, and you want to, please post them here and let them be confirmed by other users. If you can attach .blend file and steps to reproduce it I think this could be of a great help for developers.

Ok, me first :slight_smile: (images are thumbnails, clic on them to enlarge)

1. Spotlight multishade and mirror objects bugs

Steps to reproduce bug 1:
1 - a mirror object in your scene;
2 - spotlight set to cast soft shadows with Multishade option enabled;
3 - an object beetween the mirror one and spotlight;

the light actually casts soft shadow on mirror object but the surrounding object shadows reflected in mirror object are grainy and there is no way to get rid of that noise, no matter how high you set samples number in light panel.
– .blend file here –

Steps to reproduce bug 2:
1 - a mirror object in your scene;
2 - spotlight set to cast soft shadows with Multishade option disabled;
3 - an object beetween the mirror one and spotlight;

result, the light casts no soft shadows on the mirror object, it casts hard shadows instead.
– .blend file is the same, just disable Multishade –

2. Indirect lighting - color bleeding doesn’t take in account textures, only diffuse color.

Steps to reproduce the bug:
1 - a plane with diffuse color set to whetever you like (green in my .blend) and a texture with different colors in it (blue and orange for me);
2 - an object to cast colors irradiance on (a white one makes it more clear to spot)
3 - indirect lighting and irradiance cache set on, factor and bounces higher than one to make it more clear;

odd effects, where suzanne touches the ground she is green instead of blue/orange. irradiance cache only takes in account diffuse color, no texture pixels colors which makes difficult to properly setup color bleeding for objects with multi color texture. Not sure it is more feature request than bug, but this is not bug report after all, so… :smiley:
– .blend file here –

3. Adaptive subdivision conflicts with raytracer

Steps to reproduce the bug:
1 - have a scene with an object with a material assigned;
2 - add a texture to the material and map it as displacement map;
3 - enable subdivision in render panel and render;

the object is actually subdivided and displaced, peeks are correctly handled but gaps are rendered completely black. I’ve enabled AO, envlight and indirect light. The only way to avoid this is to switch to AAO instead of the raytraced one.
– .blend file here –

4. Adaptive subdivision is ignored by mirror objects

Steps to reproduce the bug:
1 - an object with a material assigned and a texture mapped as displacement map;
2 - a mirror object which reflects subdivided one;
3 - enable subdivision in render panel and render;

subdivision algorithm is completely ignored by mirror objects that only display a regular subsurfaced object with displacement map on it.
– .blend file here –

5. “Shadow only” material wrongly reflected in mirror objects (reported by Shatter)

Steps to reproduce the bug:
1 - an object with a material assigned and “shadow only” option checked;
2 - a mirror object reflecting the “shadow only” one;

the shadow only material shows issues in the mirror object, it’s completely dark. If you enable IL and cache then the shadow underneath is also corrupted.
– .blend file here –

6. “1 bounce IL” problem and a bunch of other issues in recent builds)

As many others did in the past months, I’ve given a try to the test render scene discussed on this thread, the .blend here.
At the time that discussion started, every render25 branch build was rendering that scene like this:

As you can see it looked quite good and the only noticeable issue was the aliased reflections in the mirror objects.

Now things seem changed a lot and latest builds give quite strange results.
Let’s start with the good news, well actually there is only one, we now have antialiased reflections :yes:

Then bad news… we lost everything else :eek:
As you can see below the same scene re-rendered in a recent build seems do not take into account lights, shadow, indirect lighting at all! With 1 bounce you have this, it’s seem direct ligh only:

but with 2 bounces the situation doesn’t improve so much, all goes overexposed and we have bland color bleeding (not light diffuse reflections as in first image) and not light and shadow reflected in mirror objects:

– .blend file here –

I got this strange purple blotch in the internal renderer in trunk, I should really reproduce that and report it.

I also spotted some issue with ray trace shadows not showing up in the mirror reflections:

while for some reason mirror reflections are aa now.

added two bugs for new adaptive subdivision feature

I wouldn’t count the last two as bugs, these were mentioned as not (yet?) supported when it was introduced. And they are really the same bug, it isn’t supposed to work with raytracing so it won’t work with anything that uses raytracing.

at its first introduction subdivision didn’t showed that black spots all over when used with raytracer, as you can see here (I rendered it 2010 March 8):

so I consider this a bug.
Anyway, even diffuse color for colors blending could be considered a feature and not a bug because this is the way it is actually implemented. But results are wrong as they are for subdivision.

I’d like to list here more a reminder than a bug tracker so I think it should be good to have even those things reported :slight_smile:


there is another missing feature or bug:
The material based subdivision is not correctly raytraced for shadows
Could the black area in your image be what is the glowing issue in my rendering?

You can see that somewhat at the medium point for the displacement all geometry which goes inside
gets indirect lighting glow.

Everything that sticks out does not.


The shadow issue is also there with buffered shadows. I added a mirror behind this scene and noticed that Blender slowed down to a point just canceled it.

If this is intended not to work with Raytracing then this whole render branch renders itself useless for me.

I get the feeling it is nothing more then some simple and basic 1 bounce indirect lightning with basic color bleeding
and thats it.

A reflective sphere over a material with “shadows only” checked

Is that supposed to be the shadowed side of the scene, I mean is the light beyond those objects, am I right? If so maybe it can be the “other side” of that bug, yes :yes:

@ cekuhnen and shatter:
I’ll test them and if I can reproduce the bugs I’ll add them to the list in first post.

this is the other side of my scene and I don’t get glowing gaps here,

maybe I didn’t understand correctly… can you share your .blend?

yes those are the shadow sides!

The color issue is also in the front.

However in addition the front also has black artifacts on the surface which have no
texture displacements and are set to smooth.
The cube ok should be set to flat to look ok. But the sphere should be ok with smooth.

here is the blend file:

I do not know the intentions of it, I only remember it being non-raytracing when introduced. Hopefully that will change.

it seems glowing artifacts in your blend file appear only when you turn indirect lighting on, if you turn it off you get black blotches instead:

but the odd thing is:
if I turn IL off or on in my scene I still got black blotches and no glowing effect, no matter where the camera is, so I don’t really know how to fill this bug in and what parameters influence the differents behaviour from one scene to another… :spin:

I added your bug to the list

The glow blotches are linked to indirect lightning - yes.

Well I deleted the renderbranch build on my desktop.

I am done with wasting month of time of hoping and toying with it.

it seems this branch is getting zero attention after durian… :frowning:
added bug number 6

Its future has been discussed among the devs. It looks like it has to wait for the new shading system, but brecht hasn’t signed any contract which keeps him from working on rendering in blender so he’ll be able to help out in the future too.

I wrote bender internal off for my type of work.
Given the situation it seems more realistic to focus on external solutions.

I mean this is an OSS project so development can only happen when
manpower is there.

Blender can stil be used for modeling texturing and post-pro.
And it is great at that.

With Ptex coming and the high-poly sculpting work, Blender can be used for that as well, I can see Lux and Yafaray seeing their exporters developed to eventually have those supported as well. Though both may need some dev. work to actually render Ptex textures.