[JPMays]

Hi all,

I am having some trouble with a rendering from SU8 Pro. See image.



I'm getting a lot of grain, even though it rendered to SL18. Also, it seems many of my materials are relfective, in the sense that you can see a red glow in the back off the red linoleum floor, and even a slight blue glow above and to the right of the TV, from the couches. Is that a problem with my lights, or the materials themselves? Both the linoleum and fabric have roughness of about 99.

I appreciate everyone's advice.

[JDHill]

Would it be possible for you to send me this scene (the native SU file -- jeremy at nextlimit dotcom)? I am trying to examine an issue which may possibly be similar, regarding a unknown issue in the engine, but it is extemely difficult to isolate. My hunch is that your scene is displaying the same issue. I can't really say more than that without seeing the SU file though, because I cannot determine whether I'm looking at this particular issue, or something totally unrelated.

[JPMays]

I can send it to by YouSendIt, probably, but some of the materials are linked to mxm files saved elsewhere. Is there an easy way to pack everything?

[JDHill]

Not really, when it comes to MXM files -- exporting an MXS with Pack and Go enabled will get everything but those.

[JPMays]

You Send It wouldn't work, so I'm attempting to share it with you via Google docs. It's a pretty big zip file, 45Mb.

[JPMays]

Nvm, apparently You Send It did work. Sorry for the double send.

[JDHill]

Thanks, I got the files; however, could you please also send the SketchUp file, so I can inspect how the MXS was generated, and not just the end result?

[JDHill]

Looking at the MXS, I don't see anything technically wrong from the plugin's perspective, so you probably don't need to send the SKP. As far as the image not being as clear at SL 18 as you wish, you may be able to implement a few optimizations to help with that:

• there are several materials in the scene which are using pure or nearly-pure white in Reflectance 0°.
• minor, but the FINE BRUSHED STAINLESS STEEL flat material is strangely created as a dielectric.
• you may consider putting some ground outside the windows, as it's not too realistic to have the sky shining upward through them.
• rather than building your grid & circular lights physically, you may consider using simple rectangles, and creating the grids & circular light shapes by means of mask textures in the emitter material.

Regarding the last point, it would be cool if the plugin added a mask map in its emitter material character just for this purpose.

Regarding the reddish color bleed, it appears that this may be correct, being the result the fact the ceiling is lit almost entirely by the numerous down lights in the area (i.e. it is lit by light reflecting off the red floor). Even when that's not the case, such bleed may be noticeable:



However, the determination of whether or not it's correct is complicated by the fact that I am seeing a bug related to global bump; disable global bump in your blue Furniture material and you should find that the bluish cast no longer appears on the cabinetry below the television.

Global Bump on:


Global Bump off:


The wall behind the television is still bluish, because the material it is using (Rain) is bluish. I will have to try to create a simpler scene reproducing the global bump issue and have the engine developers check it out.

[JPMays]

Ok, thanks JD. I will try to adjust the reflectance 0 settings, and use a different stainless steel material (I didn't like how that one turned out anyway). Regarding the lights, I agree it would be cool to add a mask map to emitters (sidenote, can that be done to non-emitter materials in the SU plugin?). I will do this too.

I will disable global bump on the furniture, and I guess just accept the red reflection.

The ceiling seems so dark though, even though it is pretty close to a pure white material (253). What would you recommend to lighten it?

[JPMays]

I'm trying to make the emitter with a clip mask, and cannot get it to work. When I view it in the material editor, it looks just like a regular emitter, with no grid. When I link a material to it in my model, it does not emit (I checked the reverse side too). I'll send you the mxm so you can check it out too. Thanks.

[JPMays]

Also, how do I disable global bump? That feature is not readily apparent to me.

Thanks,
JP

[JDHill]

Sorry, but I can only do so much diagnosing at the moment, as I am out of town at Siggraph this week. You cannot avoid using global bump if you use an embedded plugin material with bump, since that's how the plugin does bump. However, if you're using an MXM, it's easy: remove your bump map from the Global Bump channel found in the top material node, and put it in your BSDF bump channels. Regarding your grid emitter, it looks like you are trying to create it Maxwell 1.x-style using weight-mapping and ghost layers, etc. You don't need to do that anymore -- just start with an empty material, then add an emitter; select the emitter's parent Layer node, and put your grid in the Opacity/Mask map. Same goes for when you want to layer one set of BSDFs over another.