1.
Is there a way to do something similar to Softimage's Freeze Modeling?

Eventually I want to get really good at procedural modeling and even organic procedural modeling. But for now, and for just prototyping things quickly, I think clearing the modeling history and just dealing with a polygon object that has no history is quite useful.

Just like if I were to import an .OBJ to houdini, I wouldn't get the history that got it to that stage of development, so besides exporting to .OBJ and re-importing, how is this done?

2.
Collapse points for snapping?

3.
Best way to set up a mirror group so you can model 1 half and see the other side update as you go

4.
Tweak Component Tool & Proportional modeling?

5.
more snapping stuff. In Soft, you could snap to points from the same object, but you could do this on a per axis basis. So if you want to line up one (or more) points in relation to another point, or grid, etc. (often in conjunction with collapse points for snapping asked above)

6.
Where are centers? Is pivot the same thing? For example, I often work with cube geometry to start modeling, but I often like to put the center at the bottom of the cube and have it sit on the grid plane instead of being intersected by the grid plane.

^And this way when used in conjunction with various snapping, I can arrange my objects easily by snapping them to the floor, or onto other surfaces like a table with ease

Regarding number 1, this is the freezing, there are two ways to go for this.

- The first one will sound you strange because you´re approaching this with a “SI-brain” mode, but it´s the best one actually. If you press the red flag on the final node of your SOP network, you are actually locking the geometry, this is, forcing Houdini not to calculate anything above this node. As every Houdini node is not just the operation but also all the resultant geometry, this means, you´re actually freezing the geometry BUT should you ever regret it, you still have all the nodes there to change it again. It´s like disconnecting the history, but still having it there in case you needed it.
If it visually bothers you to see all the nodes there, you just create a new geometry node, and use “Object Merge” to bring that locked node in. Voila. Just one node with your geo, and you can always re-tweak it in the future.

- As an alternative option, it´s very common for Houdini users to cache the geometry (.bgeo format) to a file and reload it with a File node, efectively erasing all traces of history.

1. File Cache SOP is the best solution, you can save bgeo to file and load it from disk. When you change something up the chain just reload geometry.

There is Cache SOP that do caching to the ram, so this last as long as you have enought ram or you don't close Houdini.

You can lock each SOP (red square witch padlock icon). That way it saves result of this SOP to the hip file. To recook just unlock a relock again.


2. Fuse SOP

3. There is always more ways how to do something. E.g. you can put Mirror SOP at the end of the chain, set display flag to Mirror SOP (or pin viewport to Object level/context) and put modeling actions before Mirror SOP. (New SOPs append behind last selected SOP)

Edit SOP has also own mirror options.

4. There is Edit SOP (but not as nice as Tweak Component Tool) There is Soft Radius parameter (but it works only on Points and doesn't allow you to tweak exact falloff of radius and strenght with curves as Proportional Tool)

5. Snapping is weak and buggy. (Fuse SOP have some additional snapping option on Snap tab) Wait for next version, look there:
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=143732#143732 [sidefx.com]

6. Pivots are centers. There is Ins key for permament pivot modification and ' key for temporal pivot modification (as Alt key in XSI)

Look into help or search forum please.
http://www.sidefx.com/docs/houdini13.0/basics/objects [sidefx.com]

6.
It doesn't look like “pivot” is quite the same as ‘center’….

For example, i made a box, pressed insert, moved the pivot to the bottom of the box. However, this had no effect on the xyz the translation, which was left at 0,0,0 even with a new pivot position. Due to this, zero'ing out the translation field won't pop the box model to the top of the grid plane.

Not a deal breaker or anything, I guess it's mostly just for rotation, softimage center's are for more than just rotation as explained above.

Derek Mondelli
6.
It doesn't look like “pivot” is quite the same as ‘center’….

For example, i made a box, pressed insert, moved the pivot to the bottom of the box. However, this had no effect on the xyz the translation, which was left at 0,0,0 even with a new pivot position. Due to this, zero'ing out the translation field won't pop the box model to the top of the grid plane.

Not a deal breaker or anything, I guess it's mostly just for rotation, softimage center's are for more than just rotation as explained above.

I think the insert pivot thing in Houdini was inspired from Maya (bad idea in general to adopt anything from Maya) and it's more or less the equivalent of XSI's alt key when in a transform mode in order to visually change the pivot of your transform, which as you know, it's a visual/temporary thing it doesn't really change the pivot (center) of the object.

No matter how you change the pivot it doesn't affect translation… Go see for yourself

Derek Mondelli
No matter how you change the pivot it doesn't affect translation… Go see for yourself

Well, I would if I'd manage to activate the pivot, but I can't seem to be able to…

For number 6:

Channels and basic expressions can go a LONG way.

If you right click on the Y size of your cube, click on Copy Parameter.
Then right click on the Y Center and then Paste Copied Relative Reference you'll get a “ch(”sizey“)” in the box. Simply add a /2 to the end of that to get “ch(”sizey“)/2”.

Now no matter how tall you make that cube in the initial box node, the bottom will always be at the grid. Add a transform sop, which defaults to the origin of the world and you can rotate the cube from the bottom.

Channel Referencing is pretty big in Houdini and usually just involves basic math and logic. Don't be put off because its a little text and confuse it with “programming”.

I could be missing something but the above answer to #2 has me baffled, I'm playing with fuse sop but it doesn't seem remotely simillar to how and why the collapse points for snapping toggle is used in softimage. A soft user will understand what I mean, and maybe can figure something out.

Probably not a big deal, I just always use that, sure there are other ways.

Insert key (pivot) change (set) the new values for pivot.
' key doesn't change (set) values (it only temporally alter them for transform tool, like Alt key without lock)

Pivot is more for rotation then translation as translation doesn't depend that heavy on pivot position.

For Box SOP you can change center parametr.
But far easier is append Transform SOP. Look at example.
(This is explained in almost any basic tutorial for Houdini)


For the #2 If you search for something like Weld Points toggle button in Tweak tool it isn't there. You have to snap the points and then Fuse them together. Or please specify what is exact name of that toggle in XSI.

#2.
The exact toggle in Softimage is “Collapse points for snapping” in the transform panel

basically if you have like a row of vertices, that were not lined up, running down the neck, lips, nose, forhead and back of the head/neck, you could just select them all, then with this toggle on, snap them to 0 on the X-Axis only using grid snapping, and all of the points align, just in the X axis.

It's got nothing to do with welding.

Do you have a link to a tutorial movie for the Collapse points for snapping?

Houdini may or may not have it but it's always easy to check if you can show us

Thanks!

Netvudu
Regarding number 1, this is the freezing, there are two ways to go for this.

A third way might be to just select all the nodes above and hit Shift+C to collapse them into a subnet, and then lock the subnet. So the history is hidden from view and also disconnected until it is unlocked.

Derek Mondelli
#2.
The exact toggle in Softimage is “Collapse points for snapping” in the transform panel

Thanks Derec, I didn't used that toggle, but it is fast. I do scaling to the zero first then snapping instead (oldschool but works too).

Look at hip file how to use the Fuse SOP for similar snapping but it's not as interactive nor fast as Collapse points for snapping in XSI.

Edit: I added short video demonstration how this functionality behaves in XSI (First point transform is with Collapse points for snapping On, second one is with this feature turned off)

+1 for Collapse points for snapping

Derek Mondelli
4. Tweak Component Tool & Proportional modeling?

You can do some of the SI Tweak using the Edit tool, but only for points or primitives. eg.
- First, hide the handle. Right-click on it and turn off the Display toggle
- Now you can select and drag points (when in point select mode)
- Or you can select and drag polygons (when in primitive select mode)

Also in the Edit tool, you can do proportional modeling on point selections by changing the soft radius. The shortcut for this in the Edit tool is to middle-mouse anywhere except the handle and drag.

That works pretty well, I don't even need to hide the handle really, and thanks for the MMB drag tip, however…

This major difference here is that there is a constant step of ‘selecting’. The big thing about the Softimage tweak tool, is that you select and move in one stroke, it's not a two part process. This makes it fast, combined with the fact that you are also never switching between points and polys, you just drag what you need as you need it and sculpt a form quickly, sometimes with a soft radias (proportional modeling) and sometimes without.

Also, Proportional modeling had a great option if you dig into it known as “consider neighborhood”. So if you were sculpting a pair of lips, the radius would understand that you didn't want to have any effect on the upper or lower lip depending on where you primarily grab from. This works great for lips, eyelids, also for adjusting the arms of a character, you never accidentally move points on the upper torso even when working with a large soft radius.

It's these little, subtle things, that I think would be great additions to Houdini and don't at all effect it's procedural framework. I for one am very, very excited for the possibilities to come.

For now this will work fine, I'm just going to be a lot slower for the time being.

You should be able to just click on a point and drag it as well, although possibly a bit slow on the initial pick.

edward
You should be able to just click on a point and drag it as well, although possibly a bit slow on the initial pick.

Yes I had noticed that, however this doesn't seem to work once “soft selection” is enabled.

Hello, I'm visiting this thread for the “ Collapse points for snapping ” function.
Thanks Pezetko for the files. I saw the Houdini scene file and it seems , with Fuse, you need to snap on the grid? Or is it possible to snap on points too? What would be the steps to achieve that?