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Member Since 25 May 2008
Offline Last Active Sep 27 2012 10:44 PM

Topics I've Started

Extrusion

12 September 2012 - 07:28 PM

Hi,

Does anyone actually know how to extrude and edge or vertex or face because everything I have tried to do has failed.

Is it a magic trick, only known to the inner circle ?

Whats the rub, hows it done, because I have tried everything and I have not got a clue.

If the vertices are orthogonal and centered round the origin, no problem just add a scaler but what if they are not and most of the time they wont be, so whats the deal ?

Cross product on edges don't seem to get anywhere ?

Dot product times a cross product ?

I have been stuck on this for so long and would really appreciate some help, for instance if I were to say actually how many years you would be shocked but yes it is years.

So, please if you might know how to do this, if you could let me know, thanks.

Cross product problem

09 September 2012 - 02:26 PM

I have encountered a problem with a cross product calculation that I would like some help with if possible.
The problem is that I can create a vector that is perpendicular, ninety degrees to one of the axis but I want the vector to be perpendicular to both axis. The code for the cross product is like this and this creates the object in the images. The original quad is originally set to be very un orthographic (very un centered ) on all axis as a test.

I then brought the object into another application to get a better view of the object.

Your help would be very much appreciated with this.

The code :


pv1->x = vtx[p].pos.x;
pv1->y = vtx[p].pos.y;
pv1->z = vtx[p].pos.z;
pv2->x = vtx[p1].norm.x;
pv2->y = vtx[p1].norm.y;
pv2->z = vtx[p1].norm.z;

D3DXVec3Cross( v_res,
pv1,
pv2 );

vtx[4].pos.x = v_res->x;
vtx[4].pos.y = v_res->y;
vtx[4].pos.z = v_res->z ;

Returns a result of :

Posted Image


Posted Image

Posted Image

Edit Gradient and Rotation

02 August 2012 - 09:46 PM

Hello,

I have been working with vertex selection and processing .I am starting off with a cube I then select some vertices then rotate the cube around the y axis by 45 degrees. Having spent some time on this I have found that by giving various values to each vertex I can derive an x direction edit and an x, z edit that look okay..

So, I guess the principle behind this type of processing is a relationship between the rotation of the mesh / vertices and the values that are passed to the edit functions, like a gradient I suppose.

So, what I would like to know, is what type of maths is this and how can I follow it up. For instance is this type of thing a derivative or deviation or something like that or is it some type of ratio deviation or derivative.

any suggestions greatly appreciated.

Lattice Deformer

30 July 2012 - 12:37 PM

Hello,

I have been turning over the concepts of lattice deformers, with a little glass of Vodka and have been musing a while turning the ideas over and kind of thinking them through.

So, from what I understand, a lattice deformer changes the coordinate system of the local geometry, i.e changes the volume of the local coordinate system and the lattice dictates the shape of the coordinate space.

And when a deformer is applied to an object that exists in model space some type of process is applied to the objects in order to translate relative coordinate space from the lattice volume to model space. Model space being projected into World space.

Or are we talking, deforming world space ?

So, the question is : how accurate is my understanding, is this about right or not quite so right ?

And, would it be possible to create a lattice deformer within Direct X ?

Small scale Software 3D Device

26 July 2012 - 10:46 AM

HI folks,

I would like to create a small scale software 3D environment that would allow me to plot vertices and then process the vertices using precision maths. The idea being so that I could check results of various vertex processes and save results to a text file for instance, so that I can then load the test data into Direct X to see what the results are. The idea being that I could then go on to develop a library that might then be used along side Direct X.

But, I am not sure how to go about trying to create a software 3d Device.

Anyone have any ideas of a good place to start ?

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