# SeanJD

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1. ## Lattice Deformer (2x2 FFD)

The above solution does indeed work! I set it up as a 2x2 lattice and didn't use the smoothstep weighting (just V.x or (1-V.x) as mentioned for basic weighting) and it works a treat. I'll try ading the smoothstep when I get a chance. Thanks for the solution Osmanb.
2. ## Lattice Deformer (2x2 FFD)

Great, I think I understand now  though I'm fairly new to 3D dev (I thought smoothstep was a type of dance music  ) I'll give it a try later and let you know how I fare with it.
3. ## Lattice Deformer (2x2 FFD)

Hi Osmanb, thanks for the explanation! I think I was close the first time around then, I have written code which can weight each lattice vertex to each model vertex but just didn't get the weights correct. Also I didn't normalize the vertex positions to be in the range 0->1 . I can do that for sure, but I'm still a little uncertain about getting the weights. I've looked at the smoothstep equation, so do i apply that on each model vertex<->lattice vertex for each direction i.e. calculate the distance between each on each axis? And by product of the three directional weights do you mean the cross product? I'm almost there but just need to get this weighting algorithm right. Cheers
4. ## Lattice Deformer (2x2 FFD)

I have been looking into this for days and not come across anything that really explains the concept, but have just come across this paper from siggraph 86 which i think explains it nicely.. http://pages.cpsc.ucalgary.ca/~blob/papers/others/ffd.pdf it uses' tensor product trivariate Bernstein polynomials' to find the vector offset from the original vertex position to that of the deformed lattice. However, before going ahead and writing the code to perform these equations could anyone confirm that this would be an adequate approach to deforming a solid geometry within the control lattice so it moves with the control lattice? I'm just so green to this that I could do with some advice of anyone who has more experience with it. Cheers
5. ## Lattice Deformer (2x2 FFD)

Hi, could anyone help me to understand how to apply a lattice deformation on a 3D object, like the FFD modifier in 3DS max: http://www.3dmax-tutorials.com/FFD__Free_Form_Deformation__Modifier.html ? I have found this thread, now closed, which is basically asking the same question but hasn't got enough information for me to understand how it's done - http://www.gamedev.net/topic/628822-lattice-deformer/ it mentions 'plug the value into the parametric equations for the deformed lattice' but doesn't explain what the parametric equations are. From my limited knowledge I thought it would be a case of setting a weighted value between each lattice handle and each vertex in the model that i want to deform, and then using that weight to affect the x,y,z positions of each vertex in the model when deforming the control lattice. But so far my attempts have failed. Could anyone help explain the equations / algorithm needed to apply a 2x2 box/lattice deformation, similar to Max's FFD modifier, or point me in the direction of an article which would explain. Many thanks