Has anyone had trouble with shadows from Guardrails? I have shadows from the posts but not from the rails. I have attached an image to show it. This is using a Type 4: W section rail. Any assistance would be awesome.

From memory I think Mark Parkinson wrote something similar on a thread. I think the reason why you don’t have shadows is because the w is actually a bitmap portraying the bumps etc and is not physically geometry that can reflect light/shadow.

Thanks Mark, as far as I am aware, rail object have geometry as proven in the wireframe views. I have fixed it. it has to do with the materials mental ray shadow properties. Tweaked them and it’s all good (see image)

Rail objects do create the full geometry of the rail if you have the “W” rail profile selected, so that’s not the problem.

The problem is likely to be related to the way that double-sided materials are being rendered. The rail has a double-sided material applied to it - without this, you would only ever see one side of the rail in rendered views.

Because a double-sided material is not native to metnal ray, it’s likely that tweaking some of the rendering settings for Mental Ray might have been necessary.

Incidentally, if you ever have trouble with double-sided materials not showing up in the viewport on both sides (but look fine in rendered output), check out this knowledgebase article from the Autodesk web site:

http://usa.autodesk.com/adsk/servlet/ps/item?siteID=123112&id=12567803&linkID=10381719

Thanks Bruce, all I had to do was unlock the shadow parameters in the basic shaders area and make sure the box it is ticked on.