Suggestions for more realistic renderings in Inventor?

[ajh_ap]

I'm a longtime Inventor user and have never really been satisfied with its rendering output, whether using Studio or the integrated ray tracing function.  The lighting is usually at one extreme or the other, being too dark or washed out.  The materials never seem quite right either, especially with metals.  And, as of IV2015, it seems that soft shadows are only present in the "Best" mode of ray tracing, which makes for some very time-consuming renders.  These factors create a fake-looking scene, which is much different than the fantastic pictures I've seen on the forums (bright lights, accurate reflections, metallic surfaces, etc.).  So, I'm thinking something is amiss with my workflow.  I've adjusted the lighting settings, played around with IBL, and tweaked my materials, but I'm not seeing much improvement.  Would anyone be willing to share some techniques to achieve better renderings?

I've attached a sample image and the part file to illustrate my point.  This was done in IV2015 using the "Good" mode of ray tracing.  My other appearance settings are visible in the toolbar.  Clearly, it has to get better than this.

[karthur1]

Have you tried turning on Reflections?  This was done with "Realistic" visual style and shadows and reflections turned on.  Looks pretty good to me, but I dont know what your really after.  Ray trace is set to "Interactive" here.

Kirk

This was done with out Ray trace on.... all shadows and relfections.

[sam_m]

I don't have 2015 installed so I can't try your file as a comparison (unless you upload a stp and I can try tomorrow, if I have time).

My thoughts on renders:

1) clean and perfect doesn't look real.  Assemblies with all the screws aligned perfectly at 90 degrees look odd, so you need to add some "chaos" to make it look more real.  With this in mind, I tend to add a slight bump-map to all textures to prevent them looking flat and perfect.  Even if it's slight machining marks on turned parts, etc.

2) Orthographic view isn't real, so also looks fake.  Use Perspective view mode and then shift+ctrl & mouse-wheel to adjust the perspective - even if it's only a very little, it's suddenly more real than something generated from Orthographic mode.

3) Avoid global lighting (might be controversial).  Personally I find the global lighting options make surface look a little weird.  I know some users like it because it can produce decent-ish results with little messing about, but personally I find it looks nicer having a normal scene without it - but, yes, you do have to mess with the brightness for the scene's ambient and individual light values a bit.  From memory, I think I use a medium ambient and medium spot lights instead of the usual low ambient and high spots.

4) A scene can add a lot too.  Have your model resing on a surface instead of floating in space.  It's a tricky one, but if I don't have a specific scene/surrounding for something I'd go with a dark grey to black scene or a light grey to white with only a little colour gradient (possibly white with a dark vignette around the render) instead of a blue to white gradient, with lots of colour-change.

and finally experiment...  😉

[blair]

Move it into the Studio section of Inventor. Use one of the default lighting scenes and then move the lights around. You may want to change the color of the lights from the default "Yellow/Cream" color. A bit of a background in photographic lighting helps.

I find currently most of the "material finishes" are architectural in nature and don't contain alot of metallic automotive finishes. I've been doing more in Showcase since it was packaged with Inventor in the Suites. 

[ajh_ap]

Thanks for the comments, guys.  I've been playing around for the last few days and I think the bump maps are a necessity to obtain any semblance of realism.  I'm not even trying for photorealistic, just something that doesn't look so perfect and over-lit as sam_m suggested.  We don't have Showcase where I work, so maybe Studio is the way to go for now -- I've encountered many glitches with the model environment light settings and just finished submitting a list of bugs to Autodesk.

Can anyone comment on obtaining soft shadows in the renderings?  I'm referring to the realistic, diffused shadows that only appear in the "Best" ray tracing mode in IV2015 (all three modes had them in '13, before Autodesk broke the rendering engine in '14).  Studio has settings for shadow softness, but they still look blocky and fake.  Is there any way to change that?  I've attached some screenshots for reference.  Also included is a STEP file of the original model for those with older versions of Inventor.

Andy

[-niels-]

I don't really use studio, but check if all the individual lights either follow the lighting style's settings for soft shadows or are set to soft shadows themselves.
That might give you a better result in Studio.

[mpatchus]

This won't answer your question about 2015 (I'm still stuck on 2012 here), but you can get some realistic renders in Studio by adjusting the materials and ligths.

I usually twaek the shadow settings for each individual light rather than the light style global setting.

[admaiora]

Hi Andy,

to see the softness of the shadow you have to adjust the Light Parameter setting.

Moreover if you use an existing lighting style with some lights you have to ensure that setting for all ,or most, of the lights.

Quickly you can choose "Use Style setting" for or the lights of the style.

The you can regulate the intensity of the shadow.

Operating on the materials is a good idea too, bumo increase a lots the quality render of the scene.

[ajh_ap]

Those are some great tips -- thank you!  I've done some more experimentation and would like to comment separately on Studio and the realtime ray tracing feature.

Studio

1.  Do you guys have suggestions for default light settings?  The parts I design are usually small (say 3x3x3") and the built-in lighting overpowers my objects.  I've tried lowering the brightness but the angles usually aren't optimal, so I've taken to creating my own lights.  How many lights is appropriate?  Do you get by with just a single spotlight or have you had better luck creating a whole scene with a sun, ground lighting, etc.?

2.  Is there a way to better align the render scene with the viewport?  My renders are always misaligned and it takes a certain amount of fudging to obtain the proper scene.  Placing cameras helps a little, but I suspect it has something to do with the aspect ratio of the viewport versus the rendered image.

Ray Tracing

No real questions here, just some observations.  I prefer to use ray tracing since the workflow is much quicker for me, but the results have been seriously subpar in IV2015.  I'm working with Autodesk to resolve some bugs and other issues, but I've attached a screenshot that shows the same part ray traced in '13 and '15, loaded from a generic STEP file both times with default settings.  Look at the contrast of the '15 render; it's terrible!  I've been able to make my renders look decent with some post-processing in Photoshop, but they still don't look as good as the older software.  I've also attached a screenshot of a similar render in Studio and the results are nearly identical between versions.  I'd be curious if anyone else can reproduce this disparity between versions.  (There are other threads on here about ray tracing bugs, but most relate to issues in IV2014.)

[-niels-]

It might help if you take the time to set up a rendering "studio" in Inventor studio.

You say your parts are usually small, so it wouldn't be a big problem to add them to an assembly where you've set up all the lights, camera's and other related things.
Then you could use that assembly as if you'd take your parts to a real photostudio.

[Daniel248]

In addition to what was suggested already, good images can be obtained direct from Inventor without even going in Studio or using ray tracing – just experiment with the lights and shadows in the view tab. Create a new lighting style and play with it. This way, you can see instantly the effects of any change you make. See attached example. Material used: steel, galvanised. Inventor 2014.

[ajh_ap]

Thanks again, everyone.  I think I'm starting to obtain better results, although there appear to be a few bugs and glitches that are making this harder than it ought to be with IV2015... mostly related to shadows and contrast (ray tracing, not Studio).  Fortunately, Autodesk has been able to reproduce the behavior in my support cases, so we'll see if they fix it.  In the meantime, I'll have to do some post-processing in Photoshop.