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View Full Version : Adding twist detail to a mesh section using weight maps - help needed



Mr Mouse
04-17-2005, 07:40 AM
I've been attempting to doodle a Horn of plenty, where towards the end of the horn their is a twist. I've been attempting to control the twist where I wish the detail to begin using weight maps - with no success.

Perhaps twist is not the right tool?
Perhaps I should straighten the mesh out first twist it and then remorph it back to it's curled shaped ( but then I 'd lose the detail of the twist?)
Or could I twist out the poly where I wish the detail to start using a 2 spiralled rail extrude.

Do I have to use point normal move along point rows where I wish to create the ridging detail I wish to twist?

I'd be grateful for any wisdom on the best and most elegant approach to achieve such a task?

Yours drowning in setting custard.


The Mouse

liquidpope
04-17-2005, 09:28 AM
I'd have (a) built it straight, then (b) twisted it, then (c) bent it into a curve.
I don't know how you'd twist it now.
Here's how I'd do it... see picture.

This is an eight sided disc, rail extruded. Were I to add more detail, I'd do it in the first step.
I'd use more complex rails to add ridges around the horn, and I'd use a more complex disc shape to add ridges along the body of the horn.

Mr Mouse
04-17-2005, 10:58 AM
Liquidpope, thanks for your advice, I followed the gyst of your method although I lazily just extruded a 8 pt disc and quickly shaped it up - adding edge bevels to the points and selecting the bands of narrow polys (that the edge bevel created) running down the length of the mesh and smooth shifted these a touch to add detail, then twisted and bent as you suggested.


How is it possible though to lessen the strength in certain areas and accentuate it in others along the length of the mesh, or to control the twist effect mainly to the end of the shape - as if a gradient or alpha was effecting it?

This is what I was trying to do with weight maps.

here's my not so fantastic result as you can see the flow from the body into the end of the horn is somewhat shambolic.

Wonderpup
04-17-2005, 12:42 PM
Hi Mr Mouse,

The weight map thing with the twist tool ought to work. Are you telling the twist tool to use the map? otherwise it will just twist the whole thing regardless.

I think liquidpopes idea of twisting it first then bending is a good one also.

Mr Mouse
04-17-2005, 03:40 PM
Wonderpup, thanks for your suggestion.
Yes I had set the tool's falloff to weightmap.
I've posted an example of the kind of results I'm getting and maybe those in the know will see my error. I've used the airbrush tool to create the gradation.

Also I've found that initially when I was painting the weight map in the backviewport (set to weight map view), if I'm correct didn't paint the weight map evenly across the surface - I later switched this to wireframe mode and watched the weight map update in the the perspective viewport which I'd set to weight shade for feedback.

Mr Mouse
04-17-2005, 07:01 PM
Posted below is a little experiment towards trying to solve my issue - however when a mesh like this is given "thickness" strange unpredictable results can occur.
Is there a way in such an object to avoid this puckering on the surface?

Wonderpup
04-18-2005, 02:01 PM
Looking at the example pic i was thinking that maybe it would work if the mesh had more resolution, like a finer graduation to work with? I appreciate you're using simple meshes for the tests, but in this case that may be distorting the result. It may be worth trying it on a more hi res object with more graduated falloff.

Mr Mouse
04-18-2005, 05:00 PM
A fair point wonderpup perhaps I am being overly skimpy on my polys and points.

I'm presuming therefore if weight maps act on the points and there's not many points in my mesh between being on or off as far as the tool's falloff is concern the modification happens in what in this case is a small area.

I had assumed for some reason (most likely complete ignorance) that the modifications twist etc would have occured where the map is switched on at 100% and would fall off when it reached zero and below?

Save me oh Lightwave Deities*from my dungeon of black custard.

yours presuming and assuming

Mr Mouse

Mdust
04-21-2005, 11:53 PM
Forgive me for I am not at my workstation at the moment but I found this thread of interest. I just wanted to plant a seed - when I get back into town I am going to work on this, for now my ideas are purely theoretical.

So with that disclaimer, have you tried the Spline Guide tool? With it you can apply a twist as well as a bend based on a spline.

It's under Modify, Transform, More.

A tutorial for the tool here:

http://www.newtek.com/products/lightwave/tutorials/modeling/splineguide/index.html

My therory is that you could use this tool to create a spline-based twist. That is, on the gradient or control points of the spline.

You could even use it to create the bend after the fact.

Purely theoretical, so again, sorry for now. I'll be back in town in a day or so.

Mdust

Mdust
04-23-2005, 01:58 AM
4 Images:

1) Spline Guide to scale object

2) Twist object

3)Twist Close up

4) Bend

Use little blue circles to control. To the right to add positive value. To the left for negative value. Up and down to position effect and finally you can have user-specified number of control points on numeric requester.

Select the actions: Stretch, Scale, Bend, Twist and Weight from the drop down list.

Just another approach to the problem.

Mdust

Edit: Notice my blue lines are pulled all out of wack for the twist action. This wont be the case if you use a higher degree setting in the twist angle.