What is “Normal”?

Hi all

These days I’m working on interactive 3d walkthrough so we
requirment is to render the plan or surfaces from one side only (we r
using direct x tech. to render the scene) .So as a 3d modeler my duty
is to make sure that plane or surface should render fron the required
side only (so i used the flip command to ) and sometimes we need to
render from bothsides without using force two sided where the problem
arises ,can anyone help to sort it out

I don’t know anything about “direct x tech”, but if you are using 3ds max, you can use 2 objects back to back if you like. One thing to keep in mind is that when you create 2 objects that are supposed to represent both sides of a single object, you need to find a workable way to keep them together in the right orientation. Depending on what you are doing (still, animation, etc.) this can be done with combinations of constraints, hierarchies or even compounds.

Another approach that keeps the object count low is to use the handy-dandy “Shell” modifier. With it you can do things like specifying 0 for inner and outer shell thickness and effectively turn any object in 3ds into an object that can be seen/rendered from both “sides”. Used in excess, this increases the face count, so be sure to keep that in mind.

There is only one drawback to the method I am suggesting as compared to Mike’s. If you plan to apply a different material to each side of a plane, say, that has a shell modifier applied, you can’t do it with a “Top/Bottom” material or a “Multi/Sub-Object” material. The same material is applied to both “sides”. This is true, by the way, even if you cut up/divide the object as an editable mesh/poly.

So now you have 2 approaches to choose from, based on your needs.

Hope that helps!

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