Here's a simple but regular problem I come up against

I've had that same problem when I've put rounds on after I did the = draft, but not if I rounded the corners first, then did the draft.

David Janes

- snipped-for-privacy@x35g2000hsb.googlegroups.com...

but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

messagenews: snipped-for-privacy@x35g2000hsb.googlegroups= .com...

draft, but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

______________

Some interesting problems you bring up, a couple thoughts:

1) The "lifting" you note at the bottom of the round on the drafted = surfaces is a product of the "rolling ball" method of round creation; = what about trying "normal to spine". 2) How noticeable is this conicality on a 1 degree draft? Obviously, the = longer the drafted wall the greater the change from top to bottom, but = still on a 1" wall, it's only .015 increase in radius. And the smaller = the radius, the more noticeable the change. However, noticeable or not, = why wouldn't most people have no or neutral reaction to the fact? 3) Re machining: the simplest way to produce this drafted wall is with a = tapered end or ball end mill. Using, as a sweep trajectory, the top or = bottom of the drafted wall, naturally produces a conical corner (larger = at the bottom than top). If a plain BEM is used instead, then we are = talking about very ordinary tool paths with dozens of ways of calcuating = the tool path, some better optimized than others, but none that are at = all stymied by a corner radius that's bigger at the bottom than top. 4) For alternative ways of producing tapered walls than the draft = feature, consider this presentation, carried in Profiles Magazine, given = by Dave Lowe at the 2002 PRO/USER conference: might actually have something in there that answers your concerns. = However, you probably won't think any is as easy as your present = extrude-draft-round method.

David Janes

messagenews: snipped-for-privacy@x35g2000hsb.googlegroups= .com...

draft, but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

______________

Some interesting problems you bring up, a couple thoughts:

1) The "lifting" you note at the bottom of the round on the drafted = surfaces is a product of the "rolling ball" method of round creation; = what about trying "normal to spine". 2) How noticeable is this conicality on a 1 degree draft? Obviously, the = longer the drafted wall the greater the change from top to bottom, but = still on a 1" wall, it's only .015 increase in radius. And the smaller = the radius, the more noticeable the change. However, noticeable or not, = why wouldn't most people have no or neutral reaction to the fact? 3) Re machining: the simplest way to produce this drafted wall is with a = tapered end or ball end mill. Using, as a sweep trajectory, the top or = bottom of the drafted wall, naturally produces a conical corner (larger = at the bottom than top). If a plain BEM is used instead, then we are = talking about very ordinary tool paths with dozens of ways of calcuating = the tool path, some better optimized than others, but none that are at = all stymied by a corner radius that's bigger at the bottom than top. 4) For alternative ways of producing tapered walls than the draft = feature, consider this presentation, carried in Profiles Magazine, given = by Dave Lowe at the 2002 PRO/USER conference: might actually have something in there that answers your concerns. = However, you probably won't think any is as easy as your present = extrude-draft-round method.

David Janes

messagenews: snipped-for-privacy@x35g2000hsb.googlegroups= .com...

draft, but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

______________

Some interesting problems you bring up, a couple thoughts:

1) The "lifting" you note at the bottom of the round on the drafted = surfaces is a product of the "rolling ball" method of round creation; = what about trying "normal to spine". 2) How noticeable is this conicality on a 1 degree draft? Obviously, the = longer the drafted wall the greater the change from top to bottom, but = still on a 1" wall, it's only .015 increase in radius. And the smaller = the radius, the more noticeable the change. However, noticeable or not, = why wouldn't most people have no or neutral reaction to the fact? 3) Re machining: the simplest way to produce this drafted wall is with a = tapered end or ball end mill. Using, as a sweep trajectory, the top or = bottom of the drafted wall, naturally produces a conical corner (larger = at the bottom than top). If a plain BEM is used instead, then we are = talking about very ordinary tool paths with dozens of ways of calcuating = the tool path, some better optimized than others, but none that are at = all stymied by a corner radius that's bigger at the bottom than top. 4) For alternative ways of producing tapered walls than the draft = feature, consider this presentation, carried in Profiles Magazine, given = by Dave Lowe at the 2002 PRO/USER conference: might actually have something in there that answers your concerns. = However, you probably won't think any is as easy as your present = extrude-draft-round method.

David Janes

messagenews: snipped-for-privacy@x35g2000hsb.googlegroups= .com...

draft, but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

______________

Some interesting problems you bring up, a couple thoughts:

1) The "lifting" you note at the bottom of the round on the drafted = surfaces is a product of the "rolling ball" method of round creation; = what about trying "normal to spine". 2) How noticeable is this conicality on a 1 degree draft? Obviously, the = longer the drafted wall the greater the change from top to bottom, but = still on a 1" wall, it's only .015 increase in radius. And the smaller = the radius, the more noticeable the change. However, noticeable or not, = why wouldn't most people have no or neutral reaction to the fact? 3) Re machining: the simplest way to produce this drafted wall is with a = tapered end or ball end mill. Using, as a sweep trajectory, the top or = bottom of the drafted wall, naturally produces a conical corner (larger = at the bottom than top). If a plain BEM is used instead, then we are = talking about very ordinary tool paths with dozens of ways of calcuating = the tool path, some better optimized than others, but none that are at = all stymied by a corner radius that's bigger at the bottom than top. 4) For alternative ways of producing tapered walls than the draft = feature, consider this presentation, carried in Profiles Magazine, given = by Dave Lowe at the 2002 PRO/USER conference: might actually have something in there that answers your concerns. = However, you probably won't think any is as easy as your present = extrude-draft-round method.

David Janes

messagenews: snipped-for-privacy@x35g2000hsb.googlegroups= .com...

draft, but not if I rounded the corners first, then did the draft.

The problem with that is the rounds become conical if you draft them after. They look different and also machining the tool is more complicated because the radius of the round changes as you move up the edge.

______________

Some interesting problems you bring up, a couple thoughts:

1) The "lifting" you note at the bottom of the round on the drafted = surfaces is a product of the "rolling ball" method of round creation; = what about trying "normal to spine". 2) How noticeable is this conicality on a 1 degree draft? Obviously, the = longer the drafted wall the greater the change from top to bottom, but = still on a 1" wall, it's only .015 increase in radius. And the smaller = the radius, the more noticeable the change. However, noticeable or not, = why wouldn't most people have no or neutral reaction to the fact? 3) Re machining: the simplest way to produce this drafted wall is with a = tapered end or ball end mill. Using, as a sweep trajectory, the top or = bottom of the drafted wall, naturally produces a conical corner (larger = at the bottom than top). If a plain BEM is used instead, then we are = talking about very ordinary tool paths with dozens of ways of calcuating = the tool path, some better optimized than others, but none that are at = all stymied by a corner radius that's bigger at the bottom than top. 4) For alternative ways of producing tapered walls than the draft = feature, consider this presentation, carried in Profiles Magazine, given = by Dave Lowe at the 2002 PRO/USER conference: might actually have something in there that answers your concerns. = However, you probably won't think any is as easy as your present = extrude-draft-round method.

David Janes

- snipped-for-privacy@v1g2000pra.googlegroups.com...

snipped-for-privacy@x35g2000hsb.googlegroups.com...

t, but not if I rounded the corners first, then did the draft.

ces is a product of the "rolling ball" method of round creation; what about= trying "normal to spine".

longer the drafted wall the greater the change from top to bottom, but stil= l on a 1" wall, it's only .015 increase in radius. And the smaller the radi= us, the more noticeable the change. However, noticeable or not, why wouldn'= t most people have no or neutral reaction to the fact?

tapered end or ball end mill. Using, as a sweep trajectory, the top or bott= om of the drafted wall, naturally produces a conical corner (larger at the = bottom than top). If a plain BEM is used instead, then we are talking about= very ordinary tool paths with dozens of ways of calcuating the tool path, = some better optimized than others, but none that are at all stymied by a co= rner radius that's bigger at the bottom than top.

, consider this presentation, carried in Profiles Magazine, given by Dave L= owe at the 2002 PRO/USER conference:

ever, you probably won't think any is as easy as your present extrude-draft=

-round method.

1) You know, I've never used "normal to spine" for a round. I've never understoof what it meant. I might try it and see what happens. 2) Not very noticeable, but if the draft is greater it is. The example I gave was a simple one, but at other times I have done things that were more complicated, using surfaces rather than the draft command. Of course in that case I can't put the round on before the surafces are created. In short, the appearance of the part is important because I work for an industrial design firm and the difference between a conical and parallel draft can be a big deal to the designer. 3) I guess you know more than me about this - I just know I've had toolmakers and model makers tell me they prefer the round to be constant along the edge. Maybe if the adjacent surfaces are not actually flat but made from surfaces the situation is different? 4) I will look at this - thanks. You know, you didn't have to post 3 times...