• Troubleshooting

    Here’s a quick guide to my most encountered problems and their quick-fix solutions.

Preventing crashes.

A bit like the grandfather paradox.. Your scene crashes, you go back in time, and throw your PC out of the window before you read this post..
Preventing crashes

Install the incremental save script (http://scripts.breidt.net/#incrSave)
Don’t rely on Autosave
Save before rendering
Save before doing anything risky
Always check 3rd party models in an isolated scene before integrating them
Import CAD into separate Max Scenes
Try not to have too many max scenes open, Auto save will be unreliable
Always re build CAD, If you must use CAD, make sure you create polylines in AutoCAD.


Auto save kicks in when you press render: Your scene is dead.
Sometimes during the irradiance map calc, it will white screen and never return.

Classics and favorite crashes

Normal map in a multi scatter object bump map.
Use a vray normal map and place your texture in this

Crashes when distributed rendering kicks in.
Probably a missing map or proxy, use relink bitmaps to find them, or delete them from the scene.

Scene crashes on open

• Possibly corrupt geometry;
• Your only option is to start a new scene and merge in your old scene into it.
• If a piece of geometry is the culprit you can try the merge by layer script, or merge just the splines, the lights, etc, then go down the geometry list in chunks until your scene crashes, then you will know what the problem piece is.
• You can back track to an earlier file.
• Re build that particular object.

Crash on render

• Possibly not enough RAM
• In Vray System tab, up the dynamic memory limit (mb) depending on how much RAM you have.
Set to roughly half or two thirds of your available RAM.
• In Vray System tab, switch the default geometry type (Auto, Dynamic or fixed)
• Test without Distributed rendering, then check the render nodes have identical plugins, scripts, mapped paths, service packs installed.
• If using multi scatter, check there are no normal maps in your bump textures. (You have to use Vray normal bump map)

Reducing RAM useage

• Instance cloned models (use object replace script to help)
• Proxy your models and replace meshes.
• All instanced objects should be in the same file.
If you are using Xrefs and the same model appears in both files (a car or tree) it will break the instancing. The same texture will be loaded twice.
• Collapse groups to meshes, save the master group in your library first. preferably proxy the mesh.
• Try using brute force rather than irradiance map or light cache as these will use more RAM.

Network rendering check list

check all machines have the same service pack for max
check back burner version
check vray version
check plugins are installed
If you have added backburner or vray spawner as a service on render nodes
Check you have only one iteration in your start up directory. If you have re installed recently, you have to remove the old services and add the new.
Check all texture maps and assets are on the network location, no locally mapped textures
Check the node’s permissions, can they read / write to your mapped drives?

Can’t access the server

If you can’t access the server or your mapped network drives check your
account credentials:
From the Windows start prompt type user accounts, manage credentials.
Check the username and password are correct.
Ensure the manager and render nodes are set to ‘static’ IP.
If not use the computer name.
You may have to refresh the network mapped drives, click on the shortcut.


check the back burner render node IP addresses.
The servers should be looking for the IP of the manager or the computer name.
Computer name is a more robust method as there is no need to use a fixed IP address.

Slow rendering

• Vray blend materials, especially glass, will take a long time.
• Check that divide shading subdiv’s is ticked.
• If there are black passes before your GI pass, there is a material with interpolate glossy reflections checked. Use Zorb to remove.
• Lots of render elements can slow down your render, especially AO with high subdivisions
• If you are increasing the global subdiv multiplier check your irradiance map subdivisions as this is increased too. Set to 8 and test.
• For textures with opacity maps ie leaves or perforated metal panels, in the material bitmap dialogue set blur to zero or lowest possible and filtering to ‘none’.

Slow rendering

• Updating instances – usually displacement, turn off in globas settings to test.
Can also be a huge amount of instanced objects, for instance from Revit files.
• Opacity mode in Vray material, options
Normal: Very Smooth and slow (best quality)
Stochastic: Smooth and fast
Clip: Sharp, and very fast
• Check material refraction glossiness and subdivs in plants.
• If you have a few pre passes before the GI calc starts this indicates there is a material with ‘interpolate reflections’ somewhere in your scene, probably on an accessory.
Turn on layers one by one and render, then hide objects to hunt it down and kill it
Alternatively use Zorb modifier modifier to globally turn off this setting for all materials.

Scene renders black

region render is on and the render res has been reduced.
the camera is in a wall.
viewport clipping is on.
lights are off or hidden.
lights are unticked in global settings
override material is on and glass is a solid material. exclude glass from override.
don’t render final image is ticked.
irradiance map max rate is lower than min rate.
no shadows or strange shadows:
shadows are turned off.
check shadow bias distance is correct to your scene units.
for a meters maybe receive shadows is off.
maybe store scene .002 is good (2mm)
in vray lights store with Irradiance map is ticked and low min max settings are set.

Flourescent green appears in render

Revit or arch and design materials are assigned, even CAD dwg can do this.
Vray scene converter will fix most problems but this script:
Material converter will remove Revit and arch design materials.
refraction depth is set too low and the exit colour is visible.

Objects don’t render

R-Click, Object properties, check visibility settings
R-Click, Vray properties, check matte object isn’t ticked

The scene looks completely stuffed

Check your surface normals are not flipped
Check if the model uses quad chamfer modifier in the modifier stack, If there is a scene units mis match then a mm value could be taken to be a meter value.
Check the units, open the file in the scene’s original units,
Some modifier parameters don’t translate well
Sweep, clone modifier, real world scale texture coordinates, extrude etc

The scene looks completely stuffed

shadows are turned off.
check shadow bias distance is correct to your scene units.
for a meters maybe receive shadows is off.
maybe store scene .002 is good (2mm)
in vray lights store with Irradiance map is ticked and low min max settings are set.
Check you haven’t accidentally un ticked a button in the render dialogue while panning through, such as the show GI only or the don’t render final image check box.

Strange lighting

Vray global settings:
Check that hidden lights is un ticked
Check that ‘show GI only’ is not ticked
If you de-instanced an ies light or vray light, check the area shadow parameters have not reset.
If you have chosen a different ies file, check the area shadow parameters
Does your light have store with irradiance map ticked?
Low IR settings?
Are you rendering with an irradiance map or light cache not current to the scene?
Does the light have include/exclude objects set?
Probabilistic lighting is on and behaving unpredictably (noisy lights)

GI Solutions

• Look at your render passes, specifically GI to see what pass is the worst affected
• To troubleshoot, render without GI
• If using irradiance map, increase your subdivisions
• Render with brute force to eliminate Irradiance map issues
• Check your interpolation samples, Default setting is 20
• Check if interpolate frames is on

Geometry troubles

•Co planar faces:
Check by rendering an ambient occlusion pass
Check by adding an edit mesh modifier and ticking show normals
Remember that one polygon is two faces.
You can turn on ‘ignore backfacing’ and delete the polys from the opposite side

Lighting solutions

• Raise the subdivisions of your Dome light
• If you are using an HDRI in the Vray environment tab, try using a Vray dome light instead.
The dome light uses importance sampling which can fix HDR related issues
• If you have vray light materials in your scene consider testing switching to direct lighting
Does the light have include/exclude objects set?
Probabilistic lighting is on and behaving unpredictably (noisy lights)

Bitmap not rendering

Check path is correct in asset manager
Check if the material is in the location
Collin Senna’s re-link bitmaps is good
Check if texture is CMYK, use RGB


Unexpectedly high reflection, not transparent;
Usually you need a thickness –
Add a shell modifier with 10mm thickness. check straighten corners.
Check if fresnel is ticked
Crazy warped refractions and reflections
probably smoothing groups
Select all polygons and clear all smoothing groups
Add a smooth modifier and don’t allow smoothing or adjust the threshold

Materials rendering too dark

This can sometimes happen with imported models.
Check the texture input gamma override.
In the bitmaps output tab check the level hasn’t been adjusted.
Is there a colour correction node on the bitmap?
Is the object excluded from lights or GI (right click, object settings, vray settings)
If all else fails drag the texture into the material editor again. This seems to reset any gamma overrides that may have been in the creator’s original scene.
Check the output of the texture hasn’t been lowered.


UVW map not displaying correctly;
open a new scene, set units to inches, use file link to import FBX by material, save file. open a new scene, set units to meters, open the file, at the units mismatch warning select re scale to scene units.
Go to the file link dialogue, bind the file.
Then eliminate all revit materials.
It’s a good idea to do a reset X Form to Revit Geometry.
Full Revit to max tutorial in the works.

Spare column!

Today my scene just crashed. No reason, it just had enough!
Sometimes your PC probably just needs a rest.
Get a can of spray air, clean all the dust out!
Make sure the fans are actually extracting heat.
Get Windirstat from ninite.com and delete all the large files on your C drive. If you have an SSD as your primary drive it can get clogged up. clear the After effects temp via the AE preferences. If you don’t use hibernate mode you can disable it in command line. this will free up an area of your SSD that’s allocated for Hibernation, and matches your RAM size.

  • Vray.

    Linear workflow in 3Ds Max & Vray.

    Quickly set up linear workflow.


  • Vray & 3Ds Max.


    Didn’t I just read that?