VRAY Woes

[Astralogic]

Hello everyone, while following a tutorial to get to grips with VRAY I have run into a snag.

 

First take a look here at page 4. scroll down until you find the part that says to create a vray light.

 

I've done that but my light looks different to the light in the screenshot of the tutorial. Mine looks like a small circle (like an omni) whereas the one in the tutorial looks like a plane with an arrow. I have created vray lights in the past and they always look like a circle at first but then somehow change to a plane with an arrow. Not this time though, I'm stuck with it as a small circle. Can someone explain to me what is happening here?

 

EDIT: Here is my scene. There's something fishy happening with the chair. At first I thought I had some reversed normals as that is what it looks like but I don't think that's it. Could someone have a look and tell me what's happening to that chair?

 

I'm also having trouble with applying two textures to the window. The texture called "Fronts and Handles" should be applied to the window frame and the "glass" material should go on the glass parts. However max will only allow me to have one of the materials applied to the whole thing. I tried polygon selection and also element selection, both parts have different material ID's so I'm totally at a loss as to what I'm supposed to do here. I have applied multiple textures to multiple parts of the same object before with no problems. I don't get :/

EDIT: I solved the texture problem by creating a multi material Should have thought of that sooner

 

Another edit: Have a look at this render of the side of the drawer handles. Why is that happening? It seems to have holes in it. The mesh looks fine in the viewports.

 

Any help appreciated.

Thanks

Edited February 11, 2012 by Astralogic

[AubreyM]

As far as the light goes you need to select PLANE from the drop down menu in the Vray light properties. Right now it is probably set to sphere.

You have holes in your mesh because of some bad verts most likely.

I am in the middle of a render so I can't look at you scene and you didn't describe enough the problem you are having with the chair for me to take a guess.

[stayinwonderland]

there's an option in the vray light set up that lets you choose: dome, sphere, plane or mesh.

 

I would suggest breaking your questions down into single questions where possible and asking for minimal input from the other forum members. Best way is to place a pic directly in the post. It's maybe a bit much to ask someone to download your scene - unless they ask. That's my opinion though.

 

Not sure about the drawer handles. It must have holes in it somewhere!

[Astralogic]

As far as the light goes you need to select PLANE from the drop down menu in the Vray light properties. Right now it is probably set to sphere.

You have holes in your mesh because of some bad verts most likely.

I am in the middle of a render so I can't look at you scene and you didn't describe enough the problem you are having with the chair for me to take a guess.

 

Well, the light seems to work perfectly, despite not looking like a plane (and it IS set to plane) so let's not worry about that anymore

 

there's an option in the vray light set up that lets you choose: dome, sphere, plane or mesh.

 

I would suggest breaking your questions down into single questions where possible and asking for minimal input from the other forum members. Best way is to place a pic directly in the post. It's maybe a bit much to ask someone to download your scene - unless they ask. That's my opinion though.

 

Not sure about the drawer handles. It must have holes in it somewhere!

 

Yeah my post was quite a jumble wasn't it, I'll keep things more concise from now on, thanks for the advice.

 

If my questions can be answered without looking at my scene then no one needs to touch it. But if it is needed it's best that I link to it.

 

So now my only problem are those holes, which I'm going to tackle right now.

 

Thanks for the help.

[Astralogic]

[ATTACH=CONFIG]47139[/ATTACH]

 

Could someone help me with this texture problem please. It's not absolutely necessary to get this fixed, but I would like to at least like to understand why this is happening. You can see the texture has disappeared around the middle of the mattress.

 

[ATTACH=CONFIG]47140[/ATTACH] [ATTACH=CONFIG]47141[/ATTACH]

 

This problem must be the verts. Any advice for cleaning that up? It's not something I could even guess at to be honest.

 

Thanks

[fredriksimu]

You've got some serious cleaning up to do where the handle meets the drawer. Waaay to many verticies/edges. The rendering shows problems typical to overlapping polygons. Clean up and the problems will go away.

 

OK. After a quick look at your scene: The vraylight was indeed a plane, but half-length and half-width was set to 0,0. That's why it appeared as only a dot, instead of a plane. Also, you're using it as a skylight portal, and so i'd say you should use vraysun, instead of a direct light.

 

UVw-map on the bed(matress) was correct as "box" but you need to set the values to correspond with the size of your fabric, not the side of the bed. That's why the texture looked distorted. I set it to 40x40x40cm and it looks ok.

(First i had to do a reset X-form on the matress. If you scale stuff up or down, the units in uvw won't make sense afterwards)

Edited February 12, 2012 by fredriksimu

[fredriksimu]

Also i don't understand the tutorials recommendations for the render settings. It's not proper LWF and many of the settings are waaay too high.

I was able to tweak the scene down to 1minute 31seconds at 1024x768px and it still looks ok. That's on an i7 with 6gb ram. (Original settings rendered at 2minutes 51 seconds)

Edited February 12, 2012 by fredriksimu

[Astralogic]

You've got some serious cleaning up to do where the handle meets the drawer. Waaay to many verticies/edges. The rendering shows problems typical to overlapping polygons. Clean up and the problems will go away.

 

OK. After a quick look at your scene: The vraylight was indeed a plane, but half-length and half-width was set to 0,0. That's why it appeared as only a dot, instead of a plane. Also, you're using it as a skylight portal, and so i'd say you should use vraysun, instead of a direct light.

 

UVw-map on the bed(matress) was correct as "box" but you need to set the values to correspond with the size of your fabric, not the side of the bed. That's why the texture looked distorted. I set it to 40x40x40cm and it looks ok.

(First i had to do a reset X-form on the matress. If you scale stuff up or down, the units in uvw won't make sense afterwards)

 

Well I did think a vraysun would have been the better choice, but I just followed the tutorial.

 

Changing the UVW map to 40x40x40cm worked perfectly. I can't say I understand why that works, but thanks anyway. Although I don't undestand how you managed to reset the mattresses xform, the button is greyed out for me.

 

Also i don't understand the tutorials recommendations for the render settings. It's not proper LWF and many of the settings are waaay too high.

I was able to tweak the scene down to 1minute 31seconds at 1024x768px and it still looks ok. That's on an i7 with 6gb ram. (Original settings rendered at 2minutes 51 seconds)

 

Almost 3 minutes eh? It takes me about 20 I don't know what most of those settings do, I certainly don't feel comfortable fiddling with them.

 

Well, I understand there is only so much hand holding I can get, I'm off to figure out how to clean up these verts on the handles.

 

Thanks for the help.

[fredriksimu]

Save some precious rendertime (since you'll want to do lots of tests in the beginning)

F10 to enter render setup. Go to settings tab. In DMC Sampler, lower Min samples to 8 and Global subdivs multiplier to 1.0

You can also do tests with noice threshold at 0.05 (you'll see more noice but it will render faster)

Also, under the tab Indirect illumination, locate lightcache and lower subdivs to 400. Irradiance map should be lowered to "very low"

That's a good start. Next thing (when you're happy with the light setup) is to get rid of the noice. Start with noice threshold at 0,005 or go all the way down to 0,001 to get minimum noice, but longer render times.

I rendered your scene at 22 seconds with noice at 0.05, so there's your major timesaver ;-)

Edited February 12, 2012 by fredriksimu

[Astralogic]

Thanks Fredrik, that's some real useful (and interesting) advice!

 

Now let me at those render settings

[trevormcinsley]

I have been going out of my mind trying to resolve a similar bug for the last hour now (hence finding this post). The render below shows the issue, it also shows that I removed all geometry and textures from the scene to isolate the cause... which is a vray sphere light. It causes no problems with anything else in the scene, only this bit of geometry (which is a book page in case you were wondering).

 

[ATTACH=CONFIG]47182[/ATTACH]

 

 

Moving the light further from the page resolves the issue but is not ideal. I have just found a fix however which is to right click on the offending mesh> open vray properties > change the geometry setting from 'default' to 'dynamic'. Why this works I have no idea, but then I also have no idea why there was an issue between this mesh and the light in the first place...

 

 

 

And now to make sure anyone else suffering from this problem can find this solution easily: vray holes mesh geometry bug error cute kittens. That should help it show up in google...

 

 

EDIT: This fix also increases the render time dramatically... I only noticed it when I tried it in the full scene and it predicted several hours just to build the light cache...

 

Increasing the poly count with tessellation or smoothing does resolve this problem, however I cannot understand why given that it did not exist on the original (and almost identical) geometry which I replaced with this new mesh.

Edited February 19, 2012 by trevormcinsley

[fredriksimu]

Have you checked the mesh for flipped polys? Select the polys that look weird and see that their normals point the same direction as the surrounding polygons. If it's an editable poly: Convert to editable mesh and make sure you have "show normals" checked.

Edited February 19, 2012 by fredriksimu

[Astralogic]

Hey Trevor that's good advice thanks for sharing.

 

It didn't solve my problem though because I have a few reversed normals (thanks Fredrik).

 

I googled for some help and found that to correct the normals one can "Select the object, then click on Geometry -> Polygon -> Align." Could someone shed some light on that though because I can't find it :/ By geometry does it mean the "edit Geometry" in the ribbon? Because I can't seem to get that tab to appear.

[trevormcinsley]

The normals don't seem to be the cause of the problem for me. I thought it might be due to using a single sided plane with vray's double sided texture since in other engines that can cause Z fighting but it is a bit too inconsistent for that.

 

The issue has cropped up in another mesh for me now too, albeit to a lesser extent. Both meshes are single sided planes and quite close to the light source so I expect that is the reason for it.

[Astralogic]

Do you know where "Geometry -> Polygon -> Align" is to be found? I do see normals pointing the wrong way, and nothing in my scene is a plane (nor does anything have a 2-sided material). I think it's likely my problem is caused by reversed normals.

[trevormcinsley]

Do you know where "Geometry -> Polygon -> Align" is to be found? I do see normals pointing the wrong way, and nothing in my scene is a plane (nor does anything have a 2-sided material). I think it's likely my problem is caused by reversed normals.

 

 

There is a View Align and Grid Align under Edit Geometry but those aren't what you want. If I recall correctly Maya's tool for transforming the normals is called Align.

 

If you select the polygons that are facing the wrong way and use the Flip tool under Edit Polygons that should fix it. Or maybe try adding a normal modifier set to Unify.