MasterVentris

Thanks for your help, with that and the following video by Vswe I have managed it.

I would look here to help you with the basic block, it really helped me: http://www.minecraftforum.net/topic/2389683-172-forge-add-new-block-item-entity-ai-creative-tab-language-localization-block-textures-side-textures/

So I have created this jar model, and I would like it to be a 3D jar as an item in your hand and in inventories. As you can see I just get the untextured block. I have seen in some example ClientProxy classes a method "MinecraftForgeClient.registerItemRenderer(<stuff>)" which looks like it does what I want. Has anybody used this who can explain how I use this method, and what else I need to put in other classes to make it work? Thanks.

Don't spiders jump at you when they attack? Perhaps take a look at the spider classes to see how it is implemented there.

Did you set it to your mod in the build.gradle file? You need to set lines 20-22 to the info relevant to your mod.