On top of competing for the first time in the F4 CADathon which requires the submission of a rendering I would like to become more familiar with renderings to show off all the beautiful aspects of our robot, so I was wondering if anyone had any tips or resources for learning how to make the renderings look as good as possible.
My team uses Inventor Studio, which is built into Autodesk Inventor. It allows you to place lights and position the camera and can produce a very high quality render if you leave it running for long enough. Placing the lights takes a bit of practice to get it right, but it can make your CAD models look very nice.
It’s primarily intended for making animations, but can create single frames at high resolutions. I’d recommend setting it to render “until satisfactory” or for at least 150 iterations after making sure that it’s set to a higher resolution than your viewpoint.
I haven’t spent time rendering things in a while, but the tricks I remember are:
- Be sure to have a reflection environment. This is a 360° image that is wrapped around the scene to provide realistic looking reflections to the model.
- Give your “matte” materials reflections, but turn the reflection intensity down and the blur up. Real “matte” objects still reflect the stuff around them, it’s just a softer reflection.
- Don’t discount the effect of high quality shadows. Shadows with a proper penumbra look better.
Weird shadows are one of the reasons that pictures in space look fake sometimes. Generally speaking, the only time we ever see scenes with one light source and hard-edged shadows are bad renders.
- Use 3 lights. One large low intensity “soft” light straight above, one medium intensity directional light facing roughly down and with the camera, and one medium intensity directional light facing roughly down and towards the camera.
Most renderers built into CAD packages will handle most of this for you, but if you can manually take control of things, those are my tips and tricks.
Personally, I tend to use either the built in Inventor Studio or Autodesk’s Rendering website. I find Autodesk Rendering to work great - and it’s all in the cloud. So far, I haven’t had any major issues with it, however, there are some drawbacks to it:
- You cannot render files greater than 200 MB. This may be an issue for some teams and their main robot assembly.
- You are limited to 16 “credits” per render. The amount of credits you use per render is based on the settings you choose (I don’t find this to me an issue for me).
Like others have already pointed out, you should definitely look into using Inventor studio. That is what I have used in the past for all of the Cadathon’s and any other renders. If you need help with how to get off the ground with Inventor studio you can message me here or on the Cadathon Slack and i’ll be happy to walk you through it. Here are some tricks I’ve learned over the years.
- Spend time getting your materials and appearances right. I tend to not like the way that the raw aluminum looks in Inventor (probably because its too shiny and lacks imperfections), so I try to make all of my aluminum parts anodized/powder coated in cad. Black materials also don’t render very well so I usually manually adjust my blacks to be more of a dark grey to get better definition.
- For the love of god switch into perspective from orthographic. If you do this alone and just take a screen shot it will come out better than an orthographic full render IMO. while you’re in the view panel take a look at the other options and see what you like.
- In rendering settings set it to render until satisfactory and just pause it when you have reached your desired level of sharpness.
- For renders that don’t display your robot on the field, change your background to white in the settings for a pretty clean look.
- You can play around with placing lights and cameras all day if you want to get super fancy but in my experience i’m better of just rendering with built in lighting modes and my model view and getting more renders done.
Some basic material / light interaction terms you should learn that will take you a long way.
Specular - reflections on a smooth surface
Diffuse - reflections on a rough surface
Both of these can have their own color properties. For specular think about those mirrored garden balls. They have the same reflectance but different color. For diffusion, look at some rubber grips on most anything. Generally, lower specular and high diffusion give them a duller look.
Reflectance (gloss) - pretty much how much light is sent back
Texture - shape and size of the bumps that make up the surface
With no reflectance, you end up with a black hole. At 100% reflectance, it won’t matter what you set the diffuse and specular to, you will only end up with a mirror.
Texture is definitely one to play with. Without textures, the models all have the same faky perfect look to them
I used to have a chart I made by play on the different levels of specular/diffuse/reflectance. I’ll see if I can dig that up later.
I’m sure someone can explain it better than I, but most things we see is due to how light is refected. If you take the time to mimic that, you’ll do alright.