Do a google for spaceframe and look at the images, theres more than enough inspiration out there.
If you want some advice on the ways to do it nicely from someone who has looked into this sort of thing a LOT (but confess to being no expert!):
1: Write up your goals for the project and make some form of specification including things that you MUST have, things that you would LIKE and things that definately should NOT be in there. Include anything relevant to the SVA or make references to specific regulations. Keep GOOD records of your work! Not only will this give you a guide, but it will also make it easier for you should you have to justify anything for SVA or engineers reports and will let you know when you are actually approaching your goals rather than letting the project ramble on in no fixed direction (a particular Mk1 project springs to mind here). Never forget a spec is a fluid document and can change in light of different info or ideas!
2: Measure everything up that you intend on using and put it into a decent 3d CAD package (Im hoping you can use CAD, it makes life easier as you dont end up cutting tubes out that are suddenly in the worng place and its a lot easier to produce drawings and know that everything is as it should be). If your using existing suspension geometry, take particularly close attention to the measurements you take here!
3: Get hold of some decent pictures that can be scaled and dropped into the CAD package that will help you define the locations of the major and minor components.
Note: If you cant use CAD or dont know anyone who does, try and do proper drawings, they will help a lot. You can still blow your pictures up and use these as a guide for the basic chassis layout and even use them to locate the major components if you take pictures of these with relevant scales and blow them up accurately, it just takes a bit more care and attention.
4: Connect the dots between the major components with tubes paying close attention to the major and critical load paths (suspension, driveline, driver seating and crash loads). This should see you with a basic chassis layout. One thing I do see a lot of is random tubes to the middle of major load bearing members (the tube that goes in front of the oil? tank in that second stanceworks photo is a good example). This is NOT good and should be triangulated back to a major load node rather than adding a hinge mid way down a load path.
5: If your doing lots of bends (not a favorite of mine but....) use seamless tube. If its all straight line stuff, use ERW tube, its a lot cheaper and will cope with the loads. Try and keep critical stuff seamless and triangulation ERW. Whatever you do, stick to bog standard CFS3 or similar mild steel tubing. There are several advantages to using more motorsport oriented tubing but the dissadvantages just do not suit home builds within a reasonable budget and the advantages are minimal in reality. Dont use stainless, youll not thank yourself for it...
6: Try to use minimal bends! If your doing them yourself you might scrap a lot of material working out how to get them accurate (not that accuracy is always critical) and if paying for them you will find they can quickly add up to a LOT of money in setup time. Also, bends are not particularly strong and can be made a LOT weaker if doing them on the cheap. Dont bend square tube, it looks nasty, destroys the strength and isnt nice.
7: Bear in mind that a square tube can be welded together, cut and mitred a fair bit easier than round tube, often costs a lot less than round tube and can be arranged for similar strength a lot easier than round tube.
8: Do your research on the tube sizes you will be using! The price of seamless tube varies massively dependant upon how commonly used it is! Id advise sticking to (or improving on if cheaper) MSA regs on rollcage material sizes. However, bear in mind that triangulation does not always need to be done using these sizes of tube, it just adds unecessary weight and expense. Bear in mind a caterham is made using inch box section and these are very strong!
9: Dont forget (doubtless you know) that TIG is very nice if done well, but it isnt always necessary nor very easy to do in some places.
10: If your going to use existing geometry and components in the suspension like uprights etc but are going to re-make wishbones and similar components, dont make these too strong, you dont want the chassis failing before these in the event of a crash!
11: Dont assume that rose joints are completely necessary in the suspension. They may look nice but they bring several problems including cost, high maintainance requirements, are very easy to put into bending which they definately dont like and they wont last particularly long during a typical winter on the roads (assuming your building it to keep). They will also add a fair bit of harshness into the suspension.
I have seen a lot of spaceframes done for motorsport or personal projects that have not been drawn up properly and whilst effective, just are not very nice or efficient. Sure they will have been done quicker but they always lack cohesion and have silly mistakes in terms of load paths and really ugly bits where strength has been added after the fact.
Anyway, a few points to think on, hope they help
.
